Nonwoven fabric and method and apparatus for manufacturing same

ABSTRACT

An apparatus for fabricating a unique nonwoven fabric which has the appearance of a woven fabric includes a supply station for parallel warp yarns, a support structure for orienting the parallel warp yarns into a cylindrical orientation, a weft yarn applicator for wrapping weft yarns around the cylindrically oriented warp yarns after an adhesive scrim has been overlaid onto the warp yarns, a heating station for activating the adhesive and a cooling station for setting the adhesive, and a cutter for severing the cylindrically formed fabric laminate so that it can be flattened and wrapped onto a take-up roller. The weft yarn applicator including a rotating drum wherein a plurality of spools of weft yarn material are mounted in circumferentially spaced relationship and a tensioner is provided for applying the weft yarn material around the warp yarns in a predetermined tension which may be the same as, greater than, or less than the tension in the warp yarns.

FIELD OF THE INVENTION

This invention relates generally to nonwoven fabric materials, toprocesses for the preparation of such materials, and to variousapparatus used in the manufacture of such materials.

BACKGROUND OF THE INVENTION

As described above, the present invention relates to nonwoven fabricmaterials and, more particularly, to a nonwoven fabric material whichmay have the appearance of a woven fabric and which is easily engineeredalong with an apparatus and method for manufacturing same by pullingwarp yarns gently bound by an adhesive material along the longitudinalextent of the surface of a cylindrical support and subsequentlyhelically wrapping weft yarns transversely around the cylindricallysupported warp yarns prior to activating the adhesive, and setting theadhesive to bond the completed product.

Nonwoven fabrics are similar to woven and knitted fabrics in that allare planar, inherently flexible, typically porous structures composedprimarily of natural or synthetic fiber materials (i.e., yarns, threads,or filaments). Nonwoven fabrics are unique in that they can beengineered to resemble woven or knitted fabrics, but they can also bemade to have superior physical characteristics over woven or knittedfabrics. Thus, nonwoven fabrics are highly influenced by the propertiesof their constituent fibers and the manner in which the nonwoven fabricis prepared. Typical methods for preparing nonwoven fabrics includemechanical, chemical and thermal interlocking of layers or networks ofthe fiber materials.

SUMMARY OF THE INVENTION

The present invention comprises a nonwoven fabric-like material. The“fabric-like” material preferably has the general appearance of afabric, most preferably of a woven fabric, and has one or morecharacteristics of a traditional cloth fabric, including uniformity oftexture, pliability, strength, appearance, and the like. One preferredembodiment of the fabric-like material comprises substantially parallelyarn fibers (or fiber-substitutes) held together in a nontwisting mannerby a series of adhesive bridges or a combination of adhesive and strayyarn fiber bridges on one side of the parallel fibers. This fabric-likematerial can be used as is, or it can be further transformed into otherfabric-like materials by further processing as described herein. Thepresent invention also provides a continuous, in-line method andapparatus for manufacturing such nonwoven fabrics in such a manner thatthe nonwoven fabric can have a variety of desirable physicalcharacteristics. The method and apparatus are further designed such thatthe nonwoven fabric can be produced at a relatively rapid rate incomparison to known systems for manufacturing wovens.

Reference to the term “yarn” will be made throughout the presentspecification and the term should be broadly interpreted to include monoand multi-filament yarns and/or strands of various materials. The yarnsmay be large or small in diameter or denier, and can be made from manytypes of materials including, but not limited to, polyester,polyethylene, polypropylene and other polymers or plastics; wool,cotton, hemp and other natural fibers; blends of natural and/orsynthetic fibers; as well as fiber-substitutes such as glass, metal,graphite and the like. It is conceivable that some of the warp and/orweft yarns may be metal and/or metal alloys such as, for example, copperand/or aluminum wire, or combinations of metal and synthetic or naturalfibers. It should also be appreciated with the description that followsthat various densities of warp or weft yarn wrap will be referenced andthese densities will vary depending upon the type of yarn as describedabove and the desired characteristics of the nonwoven product beingmanufactured.

For the purposes of this disclosure, “warp” yarn materials include anycombinations of materials or combinations of yarns that have the yarnsor fiber-substitute materials primarily positioned to run in the machinedirection of the apparatus and that are aligned in a controlled mannerbefore being treated with an adhesive material to form a fabric-like,nonwoven substrate. “Weft” yarn materials include any combinations ofmaterials or combinations of yarns that have the yarns orfiber-substitute materials primarily positioned to run substantiallyperpendicular to the warp yarn materials.

One especially preferred nonwoven fabric of the present invention hasthe appearance of a woven fabric, but is considered a nonwoven becausethe warp and weft yarns are not interlaced or interwoven, but insteadare laid one over the other and adhered together. There are severalembodiments of this product of this invention. The first embodimentinvolves the laydown of weft yarns onto a substrate comprised of aconventional nonwoven including, but not limited to, a bonded cardedweb, a wet laid, an air laid, or a spunbonded web.

In one preferred nonwoven embodiment, a bonded carded web is used as thesubstrate for the weft yarns. This web material is particularly suitedfor the nonwoven of the present invention because the carding process,by its nature, typically orients fibers in the machine direction of theweb. A fiber orientation in which the majority portion of the fibers runin the machine directions creates a substrate in which the fibers mimicwarp yarns and are substantially perpendicular to the orientation of theweft yarns. When viewed with a light shining through a product inaccordance with the present invention, the perpendicular orientation ofthe carded fibers in the web relative to the weft yarns, creates thevisual impression of a woven material.

The bonded carded web can be printed with an adhesive or, in accordancewith one embodiment of the present invention, a randomly orientedadhesive lace or scrim can be lightly bound to its surface prior toapplication of the weft yarns. This type of adhesive lace allows for theuse of a low level of adhesive by weight in a loosely applied laydownsuch that there are portions of the weft yarns that are not adhesivelyconnected to the warp nonwoven substrate. The structure, because of thediscontinuous adhesive laydown, also has a certain degree of porositywhich mimics the breathability of a woven which has a yarn-on-yarnconstruction and no film. The resultant structure has improved hand thatmimics that of a woven material. The adhesive is preferably made fromthermoplastic polymer, but other adhesives may be used includingthermoset adhesives, and 100% solid adhesives. The preferred type ofadhesive is preferably a thermally activated copolyester that on aweight basis represents about 10-20% of the weight of the completenonwoven structure. This adhesive scrim is sandwiched between thenonwoven substrate described above, and the weft yarns. Once activated,the adhesive holds the weft yarns to the nonwoven substrate.

In yet another embodiment, a plurality of warp yarns are formed into analigned group, substantially parallel and equally spaced apart. Ifdesired, different warp yarns, for example yarns of various types(synthetic, natural, yarn-substitutes) and/or yarns of various deniers,can be aligned using this apparatus, resulting in nonwoven fabricmaterials having particularly interesting and unique properties. Thisparallel grouping of yarns is advantageously fixed in place by formingan adhesive coating, printed on only one side of the warp yarns, using ahot melt roll coater. Cooling of the hot melt adhesive occurs almostinstantaneously, and the resulting product is a fixed web or substrateconsisting essentially of a plurality of aligned warp yarns and anadhesive film positioned substantially only on one side of said yarnfibers.

An especially preferred embodiment of the warp yarn material generatorused herein comprises a warp yarn aligner, through which a plurality ofindividual yarns or threads (alike or different) are passed to be placedin substantially parallel alignment. Once aligned, the yarns are nextpassed to the adhesive station, which is preferably a hot melt roll(e.g., gravure) coater. In this device, a thin film of hot melt adhesiveis imprinted on only one side of the plurality of aligned warp yarns.The adhesive does not remain as a film after application; the adhesivetypically partially separates when applied to the parallel yarns.Bridges of adhesive and/or fragments of yarn strands (each independentlywith or without an adhesive coating) form and/or otherwise extend overthe spaces between parallel yarns. These bridges hold the yarns togetherand prevents individual yarns or threads from twisting relative to oneanother.

As used herein, the term “bridges” is meant to define the physicalresult of applying a thin film of adhesive to one side of aligned warpyarns; namely a combination of adhesive strands, adhesive coatedfragments of yarn strands, and/or fragments of yarn stands which contactadhesive on two or more aligned yarns (e.g., at two or more points),such that the series of aligned warp yarns are held together in asubstantially user selected spatial arrangement, and wherein the yarnsdo not twist, rotate, or otherwise separate relative to one another dueto the presence of the bridges on one side. In other words, the bridgeslock the yarns in place in a manner selected by the manufacturer of thewarp yarn material. Upon cooling of the adhesive, a flexible, yetunified substrate web of warp yarns having the look and feel of anonwoven fabric, is obtained. This warp yarn substrate is suitable forfurther processing as a nonwoven fabric or otherwise. If desired, thiscombination of the warp yarns and adhesive may be wound onto a spool forlater handling, or formed into sheets for other uses as desired.

The preferred warp yarn aligner has a plurality of vertically displacedsets of horizontally spaced rollers. The upper set of rollers is withina horizontal plane positioned above a horizontal plane containing thelower set of rollers, though it is conceivable that the orientation ofthe sets of rollers are not an upper and lower set of rollers butpossibly a left and right set of rollers or somewhere in between so thatthe plane of the sets of rollers would be horizontally rather thanvertically displaced or somewhere in between. The rollers are alignedtransversely with each other. In the arrangement where the rollers arepositioned within horizontal planes, each roller in a set ishorizontally offset from rollers in the other set so that rollers ineach set are positioned between rollers of the other set and the outerperimeter of the rollers in one set overlaps the outer perimeter of therollers in the other set. In this manner the warp yarns which passtransversely through the sets of rollers must pass under the upper setof rollers and over the lower set of rollers contacting all of therollers in each set with an engagement are on each roller. It has beenfound that an engagement are of about 20 degrees is preferable herein,although higher or lower degrees should also be useful. At least some ofthe rollers may be roughened on their outer surface to impart avibration to the yarns, preferably in the plane of the web.

The warp yarns, e.g., from a beam of the same, are roughly aligned whendelivered to the rollers, e.g., through a comb device or otherwise, arepassed through the spaces between the sets of rollers as describedabove. The rollers are driven at a roller-face speed that is faster thanthe linear speed of the yarns. By over driving the rollers relative tothe linear speed of the yarns it has been discovered that the yarns willbecome substantially parallel. The textured rollers could be run at aspeed slower than the yarns and achieve the same effect, but overspeeding the rollers at a ratio within the range of 2:1 to 3:1 has beenfound to be very effective. Parallel alignment of the warp yarns isimportant for most nonwoven products because it results in a uniformappearance of the yarns which makes the end product look more like awoven product.

One preferred hot melt adhesive applicator is a Rototherm® hot melt rollcoater. In operation of the hot melt adhesive coating apparatus theseries of parallel warp yarns are drawn through the glue apparatus,supported by a series of rollers. A thin film web (ranging from about0.25 to 1 mil) of hot melt adhesive is continuously gravure coated ontoone side of the aligned warp yarns. The actual thickness of the film webvaries within the range specified, and depends upon the weight of thefabric, and is usually applied at from about 5% to 25% of the fabricweight. For a fabric weight of 50 g/m² the adhesive may be applied atfrom about 2 to 15 g/m², preferably at from about 5 to 10 g/m². Afterbeing gravure coated, the warp yarn substrate rapidly solidifies, fixingthe parallel arrangement and equal spacing of the yarns. The adhesivefilm web also prevents twisting or rolling of the yarns, which maintainsthe “feel” of the product. A cooling path is provided to ensure that theadhesive web is set before the substrate is collected, e.g., in a rollform, sheet form, or otherwise as desired by the manufacturer or enduser.

The yarn orientation produced in this embodiment, in which the fibersrun in the machine direction, provides a nonwoven fabric materialsubstrate in which the fibers mimic warp yarns, which can be used insubsequent nonwoven manufacturing processes to make materials that havethe visual impression aid physical feel of a woven material. Suchmaterials often exceed the physical characteristics of woven fabrics,particularly with respect to strength, resistance to tearing, fraying,and the like, without the necessity of post treatments, includingchemical treatments, to achieve these properties. Post treatments, ifdesired, could still be employed, particularly if beneficial propertieswere achieved thereby.

While the above described adhesive methods are preferred embodiments,other methods of preserving the aligned warp yarn strands could beemployed. For example, the warp yarns can be contacted with a dryadhesive layer that is heated and then cooled to bond the materials; theadhesive could be applied with a melt blown applicator; or the alignedwarp yarn strands could be bound via an adhesive to another layer ofmaterial, a film of adhesive, or a substrate comprising adhesive andanother nonwoven fabric material.

Another embodiment of the nonwoven fabric of the present inventioninvolves the combination of warp yarns and weft yarns, with the weftyarns being positioned substantially perpendicular to the warp yarns.The terms “substantially perpendicular” are used to define anapproximately 90 degree relationship of the cross-directionalintersection of the weft and warp yarns to one another. This may vary byup to about 5 degrees in either direction away from a perfect 90 degreeintersection, e.g., from about 85 degrees to about 95 degrees. One suchproduct produced in accordance with the present invention has anintersection angle of about 89.7 degrees.

In one embodiment of the cross-directional (or “XD”) apparatus, the warpand weft yarns are adhered to one another with the same adhesivematerial that is used to bond the warp yarns as a substrate. The yarndensity can approach as high as 140 yarns per inch for a single strand36 cotton count yarn. This is substantially higher than the densityavailable in the same yarn count of a conventional woven fabric whichhas a maximum yarn density of about 90 yarns per inch for the same yarn.

The use of an open structure adhesive material (e.g., scrim, lace or thelike) in the preferred embodiments of the XD apparatus allows theformation of a finished fabric structure with very good hand properties.This is due to the ability of both the warp and the weft yarns to movefreely in the positions where they are not joined by the adhesive lace.The adhesive preferably represents less than 5-20% by weight of theentire structure.

In yet another embodiment of XD apparatus, the warp and weft yarns areagain positioned substantially perpendicularly to one another asdescribed above, but instead of being joined by an adhesive scrim orlace, they are joined by a melt blown adhesive web. The meltblownprocess is well known in the art and creates micro denier yarns. Theseyarns can be laid down more uniformly than the adhesive scrim, but yetuse less adhesive in the structure. The micro denier yarns if activatedproperly will create a finished structure that has good hand, but a moreuniform appearance than the finished structure provided with an adhesivescrim.

A preferred XD apparatus used herein for joining the warp yarn materialsand the weft yarn materials includes the following components:

(a) a supply station for aligned warp yarn materials and the adhesivematerial, whether as a film, scrim or lace; or a meltblown web or otherbondable material added to the supply station,

(b) a warp yarn material delivery station where the warp yarn materialis conformed longitudinally to the outer surface of a cylindricalsupport so as to extend longitudinally of the support,

(c) a weft yarn application station through which the warp materialpasses,

(d) a heating or adhesive activating station,

(e) a cooling or adhesive setting station, and

(f) a fabric take-up station; e.g., a take-up roll, a sheeter, or thelike.

In the operation of one version of the XD apparatus, the transfer rollof warp yarn material that is produced on the warp yarn materialmanufacturing unit is transferred to the supply station and the warpyarn material is extended through the apparatus on a transfer belt fromthe supply station to a take-up station. As the warp yarn materialextends through the apparatus it is supported along the length of asubstantially cylindrical, or as an alternative a polygonalcross-sectioned, support surface on the transfer belt and the warp yarnsor fibers maintain their parallel relationship along the length of thecylindrical surface. The warp yarn material is thereby disposed in asubstantially cylindrical configuration. A drive roll is positionedbetween a take-up roll at the take-up station and a cooling or adhesivesetting station that is upstream from the take-up station. The driveroll rotates the transfer belt along the length of the support surfacethereby advancing the warp yarn material through the apparatus at littleor no tension and at a predetermined and variable speed. Alternatively,the take-up roll can be replaced with other conventional processingequipment, including for example, a sheeter, a laminator, or the like.

Prior to encountering the adhesive activating and setting stations, thewarp yarn material passes through the weft yarn application stationwhere a plurality of continuous weft yarns are wrapped around the warpyarn material with the adhesive material disposed between the warp yarnmaterial and the weft yarns. It will be appreciated that as the warpyarn material passes through the weft yarn application station it isstill in a substantially cylindrical configuration. The cylindricalcomposite structure of warp yarn material, adhesive and weft yarns ispassed through the activating or heating station where the adhesive isactivated to bond the warp yarn material and weft yarns together.Immediately thereafter, the composite structure passes through thesetting or cooling station where the adhesive is set so that the warpyarn material and weft yarns are adhesively bonded together into asubstantially fixed nonwoven relationship which has the appearance of awoven product. It will be appreciated by those skilled in the art thatother systems for activating and deactivating the adhesive can be used,such as by way of example, moisture, high frequency light, pressure orother temperature regulating systems. A cutter longitudinally cuts thecomposite structure and as the material continues through the apparatus,the material is forced into a planar configuration as the supportsurface is progressively converted from a cylindrical configuration to aflat configuration.

In one embodiment of the weft yarn application station, an enclosedrotating drum is provided that has a ring-like enclosure with aplurality of supplies of weft yarn materials on separate individualspools, cones or the like. The drum has a cylindrical axial passagealong its longitudinal axis through which the warp yarns with theoverlying adhesive pass. Each spool of weft yarn material is associatedwith a tensioner also mounted on the rotating drum that is spacedslightly from the cylindrical axial passage so as to be in closelyspaced relationship with the warp yarn material and adhesive. The weftyarn material passes through the tensioner and subsequently around aguide pin that is also mounted on the drum but immediately adjacent tothe warp yarn material and adhesive overlay. The weft yarn material,after passing through the tensioner, extends around the guide pin andimmediately onto the adhesive and is caused to be laid transverselyaround the adhesive and warp yarns as the drum rotates about its axis.The tensioner is adjustable so that the tension in the weft yarn, as itis wrapped around the warp yarn material, can be adjusted so as to havea tension the same as, greater than or less than whatever tension theremay be in the warp yarns.

In the tensioner embodiment described above, up to twelve spools of weftyarn material can be mounted within the rotating drum on a radial wallthereof even though the size of the drum can be increased or the densityof the spools within the drum can be increased so as to allow for moreor less than twelve spools. By providing twelve spools of material at apre-determined equal circumferential spacing within the drum, the drumcan be properly balanced so that it can be rotated at high rates ofspeed substantially without vibration.

In the tensioner embodiment, it is also important that the twelvespools, or however many are used, are at an exactly equal angulardisplacement relative to each other. Exact angular displacement and thepushing of the weft yarns against the next adjacent weft yarn results inthe weft yarns being precisely and controllably placed so as to optimizeweft yarn packing. If an alternative spacing is desired however, thenthe exact equal angular displacement is not necessary. In such cases thefiber spacing will be controlled by a predetermined angular spacing ofthe rolls.

The drum also has a separate power source for rotating the drum at adifferent speed than the power source at the take-up station in theapparatus which advances the transfer belt and the warp yarn materialthrough the apparatus. Accordingly, the warp yarn material can be movedlinearly through the apparatus along the cylindrical support at either aselected steady speed and/or at a variable speed, while the rate ofrotation of the drum can be at an independent selected steady speedand/or at a variable speed. This allows the weft yarns to be wrappedaround the warp yarn material at predetermined constant and/or desiredvariable spacings and also at an angle relative to the longitudinal axisof the warp yarn material. In other words, while the weft yarn materialis wrapped substantially perpendicularly to the warp yarn material, inreality it is slightly offset from perpendicular and the angle of offsetcan be varied by varying the rate of rotation of the drum relative tothe linear speed at which the warp yarn material is advanced through thedrum. For example, if the user wished to vary the average spacing of theweft yarns, the belt speed would be adjusted relative to the speed ofthe drum (one faster, one slower). Varying the degree of difference inrelative speeds changes the weft yarn to warp yarn spacing andincidentally changes the angle of laydown of the weft yarns.

In an especially preferred embodiment of the XD apparatus, severalcomponents previously identified have been modified and/or omitted, asdiscussed in detail below. The warp yarn material continues to besupported on a transfer belt and configured into a cylindrical form. Adrive roll continues to drive the cylindrical warp yarn material throughthe weft yarn application station, where the cylinder of warp yarns aresupported to allow application of the weft yarns. Heating and coolingstations are used to set the adhesive between the warp and weft layers,and the cylindrical form is cut and flattened under tension to form aunified structure having the appearance of a woven fabric.

In this embodiment, the weft yarn application station comprises anenclosed rotating drum that has a ring-like enclosure with a pluralityof supplies of weft yarn material on separate individual spools, conesor the like. The drum has a cylindrical axial passage along itslongitudinal axis through which the warp yarns with the overlyingadhesive pass. The cylindrical axial passage is fitted with a conicalaligner, which serves as the final guide for guiding the rotating weftyarns into position on the warp yarns in substantially perpendicularalignment. The conical aligner is a stationary unit, which has an angledor sloped surface directed toward the forward movement of the warpyarns. A preferred slope ranging from about 15 to 60 degrees has beenfound to be effective, with a 45 degree slope being most preferred.

Each of the weft yarns are delivered to a fixed point on the stationaryconical aligner, and from that point each yarn falls down the slope ofthe aligner and finally falls into place on the cylindrical warp fabricyarns, landing on the adhesive on the exposed surface of the warp yarns.By use of the conical aligner described herein, the weft yarns do notoverlap one another. Instead, the weft yarns slide down the aligner andonto the warp fabric. In tight packing cases, the tension imparted tothe weft yarns causes individual yarns to hit one another, whereas inloose packing cases, the individual yarns do not usually strike oneanother on the conical aligner. The individual fibers are laidtransversely around the warp yarn substrate where they contact theadhesive on the one side of the warp yarn substrate as the drum rotates.As described above, the speed of rotation may vary as desired, from veryslow (e.g., 200 rpm or less) to very fast (e.g., over 1000 rpm). A speedof about 500-600 rpm has been found to be very useful in forming thepreferred nonwoven fabrics. Tension of the weft yarns is automaticallyprovided by the centrifugal rotation of the drum.

It will be appreciated that both the tensioning of the weft yarns andthe conical aligner's guiding of the placement of the weft yarns at thesurface of the warp yarn material, in conjunction with the rotation ofthe weft yarns around the warp yarn material results in very highaccuracy of weft yarn placement. High accuracy of the yarn placement canresult in high weft yarn packing density, uniformity of the weft yarn,structural engineering of the fabric based on known placement of theweft yarns, and overall improved performance of the product.

As in the tensioner embodiment described above, a number of spools(e.g., 8, 10, 12, 14, 16, 18, etc.) of weft yarn material can be mountedwithin the rotating drum on a radial wall thereof even though the sizeof the drum can be increased or the density of the spools within thedrum can be increased so as to allow for more or less than twelvespools. An even number of spools has been found easy to space evenlywithin the drum. However, an odd number of spools could likewise beemployed, if spaced properly in the drum to maintain a balanced state.

It will be appreciated that while the nonwoven product may be heat setand given a finished high strength bond lamination while still in thecylindrical configuration on the substantially cylindrical supportsurface as described above, an alternative heat set and laminationmethod may be used.

In one preferred alternative method, post lamination treatment of thebonded warp and weft yarns may be desirable. A lamination apparatus maybe used, either as a separate unit, or as an integral part of the XDapparatus, positioned, e.g., between the drive roll and the take uproll. A laminator in this section is preferably a flat belt laminator.The nonwoven material is fed through the post laminating section under apredetermined tension and is re-heated, and re-cooled, before beingwound up onto the take up roll. The use of the flat belt laminator mayreduce curl and/or shrinkage in the cross-direction of the product andproduce a better bond.

One especially preferred laminator apparatus comprises a separate unitwith a dual belt driven, continuous pressure lamination section thatutilizes pressure, heat and cooling to bond at least two substrates(plies) with adhesive between the layers of the substrates.

Such a separate laminator apparatus can be employed to make a variety ofcomposite and/or reinforced materials. One or more of the componentparts of the laminate (i.e., the substrates or plies) may be a wovenfabric material, a nonwoven fabric web, or a mat of fibers. Adhesivematerials, preferably thermoplastic materials, are used to bond thevarious substrates in the laminate construct. These materials may bemelted and remelted over and over. When used to laminate yarns,especially polymer yarns, thermoplastic copolyester adhesives arepreferred, as these materials may be selected to have a meltingtemperature below the melting temperature of the yarns. Industrial typelaminates that may be formed using the laminator described hereininclude natural and/or synthetic fabric-based, asbestos-based,glass-based, nylon-based, flame-retardant and/or flame-resistant based,and mixtures thereof. Laminates of other materials may also be preparedas will be appreciated by those having ordinary skill in the field.

Nonwoven fabrics such as those formed on either of the XD apparatusdescribed above are one especially preferred class of materials used asthe plies or substrates in the pressure laminator described herein.Preferably, both substrates are nonwoven fabric substrates, one of thefabric substrates representing the weft strands and another representingthe warp strands. The adhesive used to bond the nonwoven substratesshould be activated by heat during the lamination process. Thecombination of pressure, heating to activate the adhesive and cooling ofthe joined substrates while still under pressure, minimizes shrinkage,sets the yarn size in the final nonwoven fabric laminate, and impartshigh strength, including fray resistance characteristics, to the finalproduct. In addition, because the laminate is being formed underpressure, the warp and weft yarns are forced into intimate contact,whereby the adhesive between the layers is spread there between, givingthe final laminate the appearance of a woven product. The adhesive iscaptured between the warp and the weft yarns, preferably in an invisiblemanner.

The most preferred lamination apparatus used for pressure bondingnonwoven substrates has an outer housing or frame in which a rectangularpressure box is mounted. The shape of the box need not be rectangular,but this shape is currently preferred. The pressure box comprises twospaced apart sections, an upper section and a lower section, each ofwhich has pressure seals along its four edges, and each of which isfurther provided with a plurality of both heating and cooling elements.Two counter rotating drive belts, an upper drive belt and a lower drivebelt, contact one another at and together run through a space betweenthe two sections of the pressure box. The belts are dimensionally larger(length and width) than the seals of the pressure box. This is necessaryto permit pressurization of the box, both above and below the two belts.One belt is driven in a clockwise manner and the other belt is driven ina counterclockwise manner. Once the belts are in motion, one end of thepressure box is the inlet (feed) end and one end is the outlet end ofthe laminator.

The lower section of the preferred pressure box is mounted rigidly tothe frame or housing, whereas the upper section of the pressure box canbe adjusted as necessary to permit access to the interior of the box.Normally, the sections are spaced apart sufficiently to permit passageof the drive belts therethrough under pressure (or in a depressurizedstate), with or without material to be laminated therebetween. Ifdesired, these positions could be reversed, with the lower section e.g.,spring mounted against a fixed position upper section.

During the lamination process, substrate materials to be laminated arepassed through a pressure seal at the inlet end of the pressure box, andinto the space between the two drive belts. Air pressure applied to theupper and lower sections of the pressure box is used to compress theair-impermeable belts toward one another, creating a diaphragm effectbetween the belts, thereby compressing the substrates situatedtherebetween. Movement of the two belts through the pressure box allowsfor the continuous feeding of substrate materials and thermoplasticadhesive. Once therein, the substrates are nipped or pressed together bythe diaphragm effect caused by the pressure applied to the belts. Thepressed substrates are then heated under pressure, melting and spreadingthe adhesive. This allows the substrate layers to come close together,preferably with at least some portions of the warp and weft yarn strandsbecoming coplanar or nearly coplanar. The heated substrates are thencooled, while still under pressure, forming the final laminate. Thecooled laminate exits the pressure box through an exit pressure seal,where it is collected as desired. When two or more nonwoven polyestersubstrates (e.g., at least one warp substrate and at least one weftsubstrate) are laminated in this apparatus, the thickness of thelaminate at the outlet end of the laminator is at least 5%, preferablyat least 10% and most preferably at least about 20% less than thecombined thickness of the substrates and adhesive, as measured at theinlet end of the laminator.

The upper and lower sections of the pressure box are equipped with aplurality of heating and cooling elements, which are used to activateand set the thermoplastic adhesive between the substrate layers. Heatingand cooling can be accomplished by any means available to the skilledartisan. For example, hot pellets, contact heating bars, radiant heatingbars, hot fluids (e.g., oil), hot gases (steam), and the like can beemployed. Likewise, cooling fluids (e.g., water), adiabatic coolingmethods, cold gases, and the like can be employed. If desired, twoseparate pressure fluids can be employed, one serving as the heatingmedium, the other serving as the cooling medium. The skilled artisan canreadily devise equivalent pressurization and heating and/or coolingsystems given this disclosure.

In an especially preferred embodiment, the plurality of heating andcooling bars located in the lower section of the pressure box arerigidly mounted, whereas the plurality of heating and cooling bars inthe upper section of the pressure box are mounted so as to float on topof the materials being laminated. This arrangement has been found to beespecially useful in the preparation of nonwoven fabrics. Shrinkage isminimized or eliminated and the final laminate has the physicalcharacteristics (feel and appearance) of a thermomechanically finishedfabric.

Advantageously, at least about 10%, preferably at least about 25% andmost preferably about 50% of the box interior at the inlet end of thepressure box is provided with heat bars, and the remainder of thepressure box, again, at least about 10%, preferably at least about 25%and most preferably about 50% of the box interior, is provided withcooling bars. The heating bars are ideally located at the inlet end ofthe pressure box and the cooling bars are ideally located at the outletend of the pressure box. If desired, multiple zones of heating andcooling could be included within the pressure box; e.g., heat/cool,heat/cool, heat/cool, etc. Alternatively, the sequence can include apreheat section, a full heating and hold, followed by a coolingsequence. The only requirements for successful lamination are the heatactivation of the adhesive and the cool setting of the adhesive, bothoccurring under pressure.

The current rectangular pressure has a pressure area about 1500 squareinches (in²). The drive belts, which are substantially non-porousTeflon® coated belts, are pressurized from both sides of the pressurebox with air (or other fluid medium) pressure of at least 2 psi,preferably at least about 5 psi, and most preferably at least about 10psi. Higher pressures can be achieved with modification of the equipmentto support and sustain the same. This pressure applied to the belts isequivalent to a compressive weight (force) ranging from about 3000 lbsto about 15,000 lbs, applied over the 1500 in² area of the currentpressure box. For laminating the nonwoven fabrics of the presentinvention, a compressive force from about 5,000 lbs to about 15,000 lbsis typical, and a compressive force of about 15,000 lbs (at 10 psigauge) has been found to be especially preferred to date. This isimportant because in a traditional pressure laminator, which uses topand bottom platens, if a weight of 15,000 lbs was placed on the topplaten to provide the compressive force to effect lamination, any beltrunning thereunder would either stop and/or break, due to the excessiveamount of friction that would be generated. Low pressure continuouslaminators of this type (continuous, 2 belt, heat/cool zones) arecommercially available. Such laminators provide a maximum of about ½ psicompressive force. This upper limit is generally dictated by beltstoppage and/or breakage.

Other and further embodiments of the present invention will be apparentfrom the following detailed description and claims, and are illustratedin the accompanying drawings which, by way of illustration, showpreferred embodiments of the present invention and the principlesthereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary diagrammatic isometric view of the apparatus ofthe present invention.

FIG. 1B is a diagrammatic vertical section taken through a flat bedlaminator that can form part of the apparatus shown in FIG. 1.

FIG. 2 is a fragmentary diagrammatic top elevation of the apparatusshown in FIG. 1 with the adhesive scrim removed for clarity.

FIG. 2B is a fragmentary diagrammatic vertical section taken through aportion of the apparatus of FIG. 1 illustrating the endless loop of thetransfer belt used in the apparatus.

FIG. 3 is a fragmentary diagrammatic side elevation of the apparatusshown in FIG. 1.

FIG. 4 is an enlarged fragmentary section taken along line 4-4 of FIG.

FIG. 5 is an enlargement of a portion of FIG. 4.

FIG. 6 is an enlarged fragmentary section taken along line 6-6 of FIG.3.

FIG. 7 is an enlarged section taken along line 7-7 of FIG. 3.

FIG. 8 is an enlarged fragmentary section taken along line 8-8 of FIG.3.

FIG. 9 is an enlarged fragmentary section taken along line 9-9 of FIG. 8and being rotated ninety degrees.

FIG. 10 is an enlarged fragmentary section taken along line 10-10 ofFIG. 9

FIG. 11 is an enlarged fragmentary section taken along line 11-11 ofFIG. 8 and having been rotate ninety degrees.

FIG. 12 is an enlarged fragmentary section taken along line 12-12 ofFIG. 3.

FIG. 13 is an enlarged fragmentary section taken along line 13-13 ofFIG. 3.

FIG. 14 is an enlarged fragmentary section taken along line 14-14 ofFIG. 13.

FIG. 15 is a further enlarged sectional view similar to FIG. 13.

FIG. 16 is an enlarged fragmentary section taken along line 16-16 ofFIG. 4.

FIG. 17 is an enlarged fragmentary isometric looking downwardly on thedownstream end of the weft yarn application station and with partsbroken away for clarity.

FIG. 18 is a fragmentary isometric similar to FIG. 17 only furtherenlarged.

FIG. 19 is an enlarged fragmentary section taken along line 19-19 ofFIG. 3.

FIG. 20 is an enlarged fragmentary section taken along line 20-20 ofFIG. 19.

FIG. 21 is an enlarged fragmentary section taken along line 21-21 ofFIG. 3.

FIG. 22 is an enlarged fragmentary section taken along line 22-22 ofFIG. 3.

FIG. 23 is a fragmentary isometric view of a nonwoven fabric materialmade with the apparatus illustrated in FIG. 1.

FIG. 24 is a fragmentary isometric similar to FIG. 23 of a secondembodiment of a fabric manufactured with the apparatus of FIG. 1.

FIG. 25 is a fragmentary isometric of a third embodiment of a fabricmanufactured with the apparatus of FIG. 1.

FIG. 26 is a fragmentary isometric of a fourth embodiment of a fabricmanufactured with the apparatus of FIG. 1.

FIG. 27 is a vertical section taken through the fabric of FIG. 24 withthe fabric being inverted.

FIG. 28 is a sectional view taken through the warp yarns of the nonwovenfabric of the present invention with adhesive being shown on theradially outermost surface of the yarns.

FIG. 29 is a fragmentary isometric of a fifth embodiment of a nonwovenfabric made with the apparatus of FIG. 1.

FIG. 30 is a fragmentary vertical section taken through the apparatus ofFIG. 1 immediately downstream of the weft yarn application stationshowing an alternative control system for laying the weft yarns acrossthe warp yarns.

FIG. 31 is a fragmentary section taken along line 31-31 of FIG. 30.

FIG. 32 is an enlarged fragmentary section taken along line 32-32 ofFIG. 33.

FIG. 33 is an enlarged fragmentary section taken along line 33-33 ofFIG. 32.

FIG. 34 is an enlarged fragmentary section taken along line 34-34 ofFIG. 32.

FIG. 35 is an enlarged fragmentary section taken along line 35-35 ofFIG. 30.

FIG. 36 is a fragmentary isometric view looking downwardly on thecontrol system of FIG. 30.

FIG. 37 is a diagrammatic side elevation of the apparatus of FIG. 1.

FIG. 38 is a diagrammatic side elevation of the apparatus of FIG. 1 withan alternative take-up system to that illustrated in FIG. 37.

FIG. 39 is a diagrammatic side elevation of the apparatus of FIG. 1showing an alternative supply system for the warp yarns and adhesivescrim to that of FIG. 37.

FIG. 40 is an enlarged fragmentary section taken along line 40-40 ofFIG. 1B.

FIG. 41 is an enlarged fragmentary section taken along line 41-41 ofFIG. 1B.

FIG. 42 is a diagrammatic side elevation of the warp yarn materialmanufacturing unit.

FIG. 43 is a top plan view of the manufacturing unit shown in FIG. 42with portions removed for clarity.

FIG. 44 is a front end elevation of the apparatus of FIG. 43.

FIG. 45 is an enlarged section taken along line 45-45 of FIG. 43.

FIG. 46 is an enlarged fragmentary section taken along line 46-46 ofFIG. 45 with parts removed for clarity.

FIG. 47 is an enlarged fragmentary section taken along line 47-47 ofFIG. 46.

FIG. 48 is an enlarged fragmentary section taken along line 48-48 ofFIG. 46.

FIG. 49 is an enlarged fragmentary section taken along line 49-49 ofFIG. 46.

FIG. 50 is an enlarged fragmentary section taken along line 50-50 ofFIG. 45.

FIG. 51 is an enlarged fragmentary section taken along line 51-51 ofFIG. 50.

FIG. 52 is a diagrammatic side elevation of the preferred warp yarnmaterial alignment unit;

FIG. 53 is a top plan view of the warp yarn material alignment unitshown in FIG. 52 with portions removed for clarity;

FIG. 54 is a front end elevation of the apparatus of FIG. 53;

FIG. 55 is a partial cross-sectional view of the preferred warp yarnalignment unit and the hot melt adhesive applicator and cooling section,with parts removed for clarity;

FIG. 56 is an enlarged fragmentary section taken along line B-B of FIG.55 with parts removed for clarity;

FIG. 57 is an elevational view of the preferred Rototherm® hot meltadhesive roll coater, showing the exit path of the adhesive coated warpyarn material;

FIG. 58 is another elevational view the preferred Rototherm® hot meltadhesive roll coater, shown in the unengaged position, showing the exitpath of the adhesive coated warp yarn material;

FIG. 59 is an elevational view of a preferred warp yarn alignmentapparatus; with the beam station; yarn alignment station; adhesiveapplicator station and cooling station;

FIG. 60 illustrates the gravure coating of adhesive on one side of thealigned warp yarns;

FIG. 61A is a magnified illustration of the adhesive applied side of thewarp yarn fabric showing the applied adhesive (dark color) and thebridges holding the fibers in a nontwisting and parallel relationship;

FIG. 61B is a magnified illustration of the uncoated side of the warpyarn fabric, confirming that the parallel fibers have little adhesivewhich passes through to the surface opposite that of FIG. 61A;

FIG. 62 is a diagrammatic side elevation of a preferred embodiment ofthe weft yarn application (XD) apparatus of the present invention;

FIG. 63 is a fragmentary diagrammatic top elevation of the apparatusshown in FIG. 62 with the adhesive removed for clarity;

FIG. 64 is a fragmentary diagrammatic side elevation of the apparatusshown in FIG. 62;

FIG. 65 is an enlarged fragmentary section taken along line 8-8 of FIG.64;

FIG. 66 is an enlarged fragmentary section taken along line 9-9 of

FIG. 65 and being rotated ninety degrees;

FIG. 67 is an enlarged fragmentary section taken along line 10-10 ofFIG. 66;

FIG. 68 is an enlarged fragmentary section taken along line 11-11 ofFIG. 65 and having been rotate ninety degrees;

FIG. 69 is a side cutaway of the conical aligner showing how the weftyarns are delivered to the warp yarn surface in a tightly packedarrangement;

FIG. 70 is a perspective view showing the weft yarns being applied atwide spacing to the warp yarn cylinder, showing how the weft yarns slidedown the conical aligner face to drop precisely down on the warp yarnmaterial;

FIG. 71 is a side view of a preferred embodiment of the pressure box anddrive belt system for the laminator of the invention in which eightheater bars (four in each section) and eight cooling bars (four in eachsection) are used for pressure lamination of nonwoven fabric substrates;

FIG. 72 is an end view of the pressure box of FIG. 71, which shows thepressure delivery system for the upper and lower sections of thepressure box;

FIG. 73 is a top view of the upper section of the pressure box of FIG.71, showing the spacing of the heating and cooling bars;

FIG. 74 is a side view of the pressure box of FIG. 71, showing themounting brackets for the upper section (displaceable) heating andcooling bars and the mounting brackets for the lower section (fixed)heating and cooling bars. Also shown is one embodiment of a side sealingelement;

FIG. 75 illustrates the side pressure seal of FIG. 74 in greater detail;

FIG. 76 is a side view of the pressure box of FIG. 71, showing thepressure box inlet pressure seal element; and

FIG. 77 is a side view of the pressure box of FIG. 71, showing thepressure box outlet pressure seal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention includes three principal nonwoven fabricmanufacturing apparatus, all of which can be used either separately forthe production of nonwoven fabric products and/or preferably which areused in combination for the manufacture of high quality, high strength,nonwoven fabrics having the hand and appearance of woven fabrics. Thepresent invention generally consists of (1) a warp yarn alignmentapparatus, which has two especially preferred embodiments, as well asthe nonwoven fabric products generated thereby; (2) a weft yarnapplication apparatus (or XD apparatus), which has two especiallypreferred embodiments, as well as the nonwoven fabric products generatedthereby; and (3) a high pressure lamination apparatus which can be usedto fuse the product generated in the XD apparatus into fray resistant,high strength nonwoven fabric. Some of the embodiments described indetail below have additional and/or alternative component parts, all ofwhich contribute special characteristics to the nonwoven fabric productsmanufactured by the apparatus.

One preferred embodiment of the nonwoven fabric manufacturing apparatus60 is shown in FIG. 1 to include an elongated in-line framework 62including a warp yarn material supply station 64, a weft yarnapplication station 66, a heating station 68, a cooling station 70, aflattening station 72 that may include a flat bed laminator 74 (FIG.1B), and a take up station 76. As will be described in more detailhereafter a warp yarn material 78 is provided on a supply roll 80 at thewarp yarn material supply station. The warp yarn material is prepared ina warp yarn material manufacturing unit, two of which are described ingreater detail below.

Warp Yarn Substrates and Manufacturing Apparatus Therefor

One preferred nonwoven fabric of the present invention has parallelyarns held in a substantially parallel and nontwisting relationship inthe form of a nonwoven, fabric-like sheet. Such materials are referredto herein as warp yarn substrates, and two manufacturing units for theformation of such substrates have been developed. In each case, adhesiveis applied to one side of the parallel yarns. The adhesive isadvantageously applied in a random pattern, forming bridges of adhesivebetween parallel yarns. These adhesive bridges provide the backbone ofthe warp yarn substrate, giving it fabric-like flexibility and feel. Thebridges also hold the parallel positioning of the fibers and preventtwisting of individual fibers.

One preferred warp yarn manufacturing unit is illustrated in FIGS. 42through 51. As illustrated therein, the warp yarn material manufacturingunit 82 includes a supply of warp yarn 84 which is passed through analignment station 86 into an adhesive application station 88 and then toa driven transfer roll 90 which acts as a rewind roll on the warp yarnapparatus and as an unwind roll on the weft yarn (XD) apparatus, asdescribed below. The transfer roll can also be the supply roll for thewarp yarn material supply station 64 of the nonwoven fabricmanufacturing apparatus. The transfer roll 90 is taken to the warp yarnmaterial supply station of the nonwoven manufacturing apparatus of FIG.1 where the warp yarn material is introduced to the remainder of theapparatus. Of course, the manufacturing unit 82 and the manufacturingapparatus 60 could be integrated thereby avoiding the transfer roll 90by passing the warp yarn material 78 directly from the manufacturingunit to the supply station.

The warp yarn material manufacturing unit 82 shown in FIGS. 42 through51 includes a framework 92 for the warp yarn alignment station 86 andthe adhesive application station 88 where an adhesive is applied to thealigned warp yarns to create a warp yarn and adhesive laminate referredto as the warp yarn material 78. It will be appreciated with thedescription that follows that at least one embodiment of the nonwovenproduct of the invention is not made from independent warp yarns, butrather is made from a substrate simply having a majority ofinterconnected fibers primarily oriented in the warp or machinedirection. One such type of substrate that has these characteristics isa bonded, carded web although other substrates may be used including,but not limited to, spunbonded nonwovens, air-laid nonwovens, andwetlaid nonwovens. In the event that a substrate that simply includesinterconnected warp fibers is used, the substrate would not be passedthrough the warp alignment station 86 of the warp yarn materialmanufacturing unit but rather directly to the adhesive applicationstation 88.

The warp yarn material manufacturing unit 82 further includes a yarnsupply station 94 which holds multiple horizontally and rotatably storedbeams 96 of roughly aligned warp yarns which are ultimately integratedinto the warp yarn material. It will be appreciated that the multiplebeams of yarns are provided to achieve a desired warp yarn density whichis preferably about 40 to 90 yarns per inch. Each beam of yarn isrotatably positioned and supported on a frame 98 in the manufacturingunit and restricted from freely rotating through use of a conventionalbrake or friction drag system 100 to allow proper feed of the yarnsunder tension into the alignment station. The yarns are pulled throughthe alignment station by the driven transfer roll 90.

The alignment station 86 includes two vertically displaced sets 102 and104 of horizontally spaced rollers 106. The upper set 102 is within ahorizontal plane positioned above a horizontal plane containing thelower set 104 of rollers, although it is conceivable that theorientation of the sets of rollers are not an upper and lower set butpossibly a left and right set or somewhere in between so that the planesof the sets of rollers would be horizontally rather than verticallydisplaced or somewhere in between. The rollers 106 are transverselyaligned with each other. Further, when the rollers are in horizontalplanes the rollers in each set are horizontally offset from the rollersin the other set so that the rollers in each set are positioned betweenrollers of the other set and the outer perimeter of the rollers in oneset vertically overlaps the outer perimeter of the rollers in the otherset. In this manner, the warp yarns which pass transversely through thesets of rollers must pass under the upper set of rollers 102 and overthe lower set of rollers 104 in a generally sinusoidal, or serpentinepath as seen in FIG. 45. The warp yarns in the preferred embodimentarcuately engage approximately 20 degrees of each roller. The yarnscould contact more or less of each of the rollers and the amount ofcontact could vary from roller to roller within a row of rollers. Thepreferred roller diameter is about 2 inches, though this diameter doesnot appear to be critical. In the illustrated embodiment there are 10rollers in each set even though varying numbers of rollers might beused. If desired, these rollers could be heated and/or cooled, whichcould be used to impart desirable characteristics to the yarns.

As can be appreciated in FIG. 46, the peripheral surface of the rollers106 nearest to the yarn supply station 94 preferably have a coarsersurface texture than the rollers closest to the adhesive applicationstation 86. It will be appreciated that the surface roughness of therollers, preferably, gradually decreases from the supply station to theadhesive application station. The surface texture of the coarsest rollerwould preferably be finer than a 600 grit sandpaper and moreparticularly it is estimated that it would be similar to a 1000 gritsandpaper. The surface texture is very fine and is provided by the useof materials similar to those used in a conventional ceramic Analoxroll. The material used to provide the surface texture is a ceramiccoating LC-4 provided by Praxair Surface Technologies of New Haven,Conn. In at least one embodiment the rollers 106 positioned at the exitend of the alignment station 86 closest to the adhesive applicationstation 88 are actually polished and, therefore, have a very smoothsurface texture.

The rollers are rotatively driven by a drive system 108 to rotate abouttheir longitudinal axes. The surface speed of the alignment rollers 106is substantially greater than the linear speed of the warp yarns as theypass through the yarn aligner. The preferred ratio is about 20:1 withthe roller surface speed at about 300 to 500 feet per minute and thewarp yarn linear speed at about 20 feet per minute. Because the rollersurface speed is so much greater than the linear yarn speed, it is easyto understand why the warp yarn beams 96 must be restricted from freelyrotating to prevent yarn overrun. Other degrees of yarn/roller contact,roller speeds, roller to yarn ratios, surface textures, and surfacetexture gradients could be used. These parameters will be effected by atleast yarn type, yarn size, and yarn material. It is believed that overdriving the yarns relieves tension and causes the yarns to relax andexpand, while the texture on the surface of the rolls 106 causes theyarns to vibrate and shake causing them to hit their neighbor yarnsthereby ultimately finding a home position approximately equidistantfrom each of their neighboring yarns. This home position is believed tobe the equilibrium position between adjacent yarns. At present it isonly conjecture as to why the yarns align in the yarn aligner, what isknown is that the yarns do become substantially aligned as illustratedin FIGS. 46 through 49.

While one preferred system for aligning the warp yarns has beendescribed, another system would be to use conventional combs to separateand align the yarns. The system used for aligning the warp yarns doesnot affect the weft yarn alignment but may affect the aesthetics of thenonwoven product. After the yarns pass through the warp yarn alignmentstation 86 they pass into the adhesive application station 88. Theadhesive application station in one preferred embodiment comprises anadhesive scrim or lace web supply roll 110 having a conventional brakingor friction drag system (not shown) to prevent free rotation and thusoverrun, an adhesive scrim or lace counter-clockwise rotating and drivencarrier roll 112, and an infrared heater 114 adjacent to the carrierroll. The adhesive web 116 passes from its supply roll 110 beneath afirst idler roller 118 (FIGS. 45 and 50) and subsequently onto the upperhalf of the adhesive carrier roll 112 moving in an upstream direction.While on the carrier roll, the adhesive web passes under the infraredheater 114 (as best seen in FIG. 45) where it is heated to a temperaturethat begins to melt the adhesive so as to render it tacky. The adhesivecarrier roll itself is internally cooled in a conventional manner with aliquid coolant 120 for example, so that only the outer surface of theadhesive web is activated and becomes tacky. Once tacky, the adhesiveweb 116 is combined or merged into the warp yarns 84 which are feddownwardly onto the underside of the carrier roll. The adhesive web hassufficient structural integrity to act as a carrier for the yarns, oncebonded thereto, and retains the yarns in parallel, nontwistingrelationship. The resultant laminate of warp yarns and adhesive isdefined as one embodiment of the warp yarn material. The warp yarnmaterial passes across the top of a second idler roller 122 (FIGS. 45and 50) and is thereafter drawn onto the driven take-up or supply roll90 for the warp yarn material where it is gathered for transfer to thesupply station 64 of the nonwoven manufacturing apparatus 60. While thewarp yarn material manufacturing unit 82 has been described as beingseparated from the apparatus 60 of the present invention, it is to beunderstood that the manufacturing unit could be integrated into theremainder of the apparatus at the warp yarn material supply station 64of the apparatus.

A preferred adhesive scrim or lace web 116 is a hot melt adhesive thatcan be heated to activate and cooled to set. An example is made from ahotmelt copolyester polymer. One such scrim. or lace is a Bostic PE120-15 Copolyester web with a basis weight of 15 grams per square meter,it is produced by the Bostic Company of Middleton, Mass. The warp yarn,by way of example, may be a 36/1 spun polyester yarn available fromBurlington Industries of Greensboro, N.C., or from Carolina Mills ofMaiden, N.C. The warp yarns 84 disclosed above can also be used as theweft yarns in a manner to be described later. Another warp or weft yarnmay be a 30/1 slub yarn (spun polyester) available from UniblendSpinners Inc. of Conway, S.C. Other warp and weft yarns includecommercially available and custom made fibers and the like.

As mentioned previously, a nonwoven substrate such as a bonded, cardedweb (not shown) could be used in lieu of the warp yarns 84 in thelaminate structure of the warp yarn material. One such nonwovensubstrate is manufactured by Hollingsworth and Vose of Floyd, Va. andidentified by Model No. TR2232. Such a nonwoven should have a basisweight between 40-60 grams per square meter with a fiber denier between1 to 5 and preferably about 1.5.

An especially preferred embodiment of the warp yarn materialmanufacturing unit of the present invention is shown in FIGS. 52 through60. FIG. 61A shows the detailed relationship between the aligned warpyarns 84 and the hot melt adhesive film 116B which holds the yarnstogether in a cohesive product. As illustrated in FIGS. 52 through 60,the warp yarn manufacturing unit 82 includes a yarn supply station 94which holds multiple horizontally and rotatably stored beams 96 ofroughly aligned warp yarns which will ultimately be integrated into thewarp yarn material. It will be appreciated that the multiple beams ofyarns (preferably formed with equal tension in all yarns) are providedto achieve a desired warp yarn density which may range from about 10 toabout 180 yarns per inch, and preferably range from about 40 to 90 yarnsper inch. The yarn density range could be larger or smaller, dependingupon the desired characteristics of the nonwoven material, as well asthe denier and surface characteristics of the yarns used. Each beam ofyarn is rotatably positioned and supported on a frame 98 in themanufacturing unit and restricted from freely rotating through use of aconventional brake or friction drag system 100 to allow proper feed ofthe yarns under tension into the alignment station. The yarns are pulledthrough the alignment station by the driven transfer roll 90.

As illustrated in FIG. 55 the alignment station 86 includes twovertically displaced sets 102 and 104 of horizontally spaced rollers106. The upper set 102 is within a horizontal plane positioned above ahorizontal plane containing the lower set 104 of rollers, although it isconceivable that the orientation of the sets of rollers are not an upperand lower set but possibly a left and right set or somewhere in betweenso that the planes of the sets of rollers would be horizontally ratherthan vertically displaced or somewhere in between. The rollers 106 aretransversely aligned with each other. Further, when the rollers are inhorizontal planes the rollers in each set are horizontally offset fromthe rollers in the other set so that the rollers in each set arepositioned between rollers of the other set and the outer perimeter ofthe rollers in one set vertically overlaps the outer perimeter of therollers in the other set. In this manner, the warp yarns which passtransversely through the sets of rollers must pass under the upper setof rollers 102 and over the lower set of rollers 104 in a generallysinusoidal, or serpentine path as seen in FIG. 55. The warp yarns in thepreferred embodiment arcuately engage approximately 20 degrees of eachroller. The yarns could contact more or less of each of the rollers andthe amount of contact could vary from roller to roller within a row ofrollers. The preferred roller diameter is about 2 inches, though thisdiameter does not appear to be critical. In the illustrated embodimentthere are 20 rollers in each set even though varying numbers of rollersmight be used.

As can be appreciated in FIG. 56, the peripheral surface of the rollers106 nearest to the yarn supply station 94 preferably have a coarsersurface texture than the rollers closest to the adhesive applicationstation 86. It will be appreciated that the surface roughness of therollers, preferably, gradually decreases from the supply station to theadhesive application station. The surface texture of the coarsest rollerwould preferably be finer than a 600 grit sandpaper and moreparticularly it is estimated that it would be similar to a 1000 gritsandpaper. The surface texture is very fine and is provided by the useof materials similar to those used in a conventional ceramic Analoxroll. The material used to provide the surface texture is a ceramiccoating LC-4 provided by Praxair Surface Technologies of New Haven,Conn. In at least one embodiment the rollers 106 positioned at the exitend of the alignment station 86 closest to the adhesive applicationstation 88 are actually polished and, therefore, have a very smoothsurface texture. As with the previously described embodiment, ifdesired, these rollers can be heated and/or cooled, to impartdistinctive characteristics to the yarns.

The rollers are rotatively driven by a drive system 108 to rotate abouttheir longitudinal axes. The surface speed of the alignment rollers 106is substantially greater than the linear speed of the warp yarns as theypass through the yarn aligner. The preferred ratio is from about 2:1-3:1with the roller surface speed at about 200 to 300 feet per minute andthe warp yarn linear speed at about 100 feet per minute. Because theroller surface speed is so much greater than the linear yarn speed, itis easy to understand why the warp yarn beams 96 must be restricted fromfreely rotating to prevent yarn overrun. Other degrees of yarn/rollercontact, roller speeds, roller to yarn ratios, surface textures, andsurface texture gradients could be used. These parameters will beeffected by at least yarn type, yarn size, and yarn material.

It is believed that over-driving the yarns relieves any tension in theyarns and causes the yarns to relax and expand, while the texture on thesurface of the rolls 106 causes the yarns to vibrate and shake causingthem to hit their neighbor yarns thereby ultimately finding a homeposition approximately equidistant from each of their neighboring yarns.This home position is the equilibrium position between adjacent yarns.At present it is only conjecture as to why the yarns align in the yarnaligner, what is known is that the yarns do become substantially alignedas illustrated in FIGS. 47 through 49.

As best illustrated in FIGS. 60, 61A and 61B, a thin film of hot meltadhesive is next applied to one side of the aligned yarns, forming a webof bridges to adjacent aligned yarns. This film is air cooled and theresulting cohesive warp yarn fabric material is collected for furtheruse. FIG. 61A is a photograph of the side of the warp yarn fabric withthe bridges of adhesive holding the fibers in a nontwisting and parallelrelationship. FIG. 61B is a photograph of the uncoated side of theparallel yarns, confirming that the warp yarn substrate has adhesive onsubstantially only on one side of the fibers. As shown in this Figure,some minor amounts of adhesive may leak through the warp yarn substratefrom the side with the desired bridges. However, substantially all ofthe adhesive remains on the side of the aligned yarns to which it isapplied. It is estimated that no more than about 10 percent, preferablyno more than about 5 percent, of the applied adhesive passes through tothe untreated side of the aligned yarns.

FIGS. 57 through 60 show the preferred adhesive application unit 88,where the aligned warp yarns 84 are passed through a series of rollersinto contact on one side with hot melt adhesive coater roller 90. Thiscoater roller 90 is driven through a trough containing molten hot meltadhesive 116A and a thin (from about 0.25 to 1 mil thick) web of hotmelt adhesive is gravure printed on one side of the aligned warp yarns84. FIG. 60 illustrates a simplified version of the application ofadhesive to one side of the aligned yarns with a gravure adhesive roller90. As illustrated, the gravure roller picks up melted adhesive 116A anddeposits the adhesive on only one side of the aligned yarns, formingbridges thereon, which yield a flexible sheet of aligned yarns once theadhesive has cooled.

FIG. 58 is a close-up view of the relationship between the adhesiveroller 90, coated with a thin film of hot melt adhesive 116A and thealigned yarn roller 122, which carries the aligned yarns 84. In thisfigure, the two rolls are shown in a disengaged mode. When these tworollers are put in contact with one another, the exposed side of thealigned yarns 84 is printed or coated with a thin film of the hot meltadhesive 116A. As the melted hot melt adhesive 116A cools the alignedyarns are transformed into a flexible, coherent sheet 116B.

As shown in FIG. 59, to ensure complete cooling or drying of theadhesive, the coherent sheet of aligned yarns and adhesive is passedthrough a station 95 in which it passes over a series of rollers to thetake-up reel 125. At the take-up reel 125 the nonwoven warp yarn fabricmaterial is collected, e.g., for further processing or for use as anonwoven fabric.

A preferred adhesive is a hot melt adhesive that can be heated toactivate and cooled to set, for example a hot melt copolyester polymer.One such adhesive is EMS Grillon 1533 copolyester, produced by EMSChemie of Sumter, S.C. The warp yarn, by way of example, may be a 36/1spun polyester yarn available from Burlington Industries of Greensboro,N.C., or from Carolina Mills of Maiden, N.C. Another warp yarn may be a30/1 slub yarn (spun polyester) available from Uniblend Spinners Inc. ofConway, S.C.

The aligned sheet of warp yarns, bound together on one side by adhesivebridges, is one especially preferred embodiment of the presentinvention. This nonwoven fabric has a unique appearance, and asdescribed above, it can be manufactured using any number of differentyarns and/or yarn substitutes, including metals such as copper, silver,gold, platinum, and the like. The bridges formed on the one side of thealigned yarns holds the material together, giving it the look and feelof a fabric product.

Wept Yarn Apparatus and Fabrics Formed Thereby

Two embodiments of the weft yarn apparatus or XD apparatus are disclosedherein, each of which positions the weft yarns substantiallyperpendicular to the aligned warp yarns. One such apparatus is describedin detail in FIGS. 1 through 7. As illustrated therein, the warp yarnmaterial 78 is passed on an endless, recycling transfer belt 124,preferably of Teflon®, along a substantially cylindrical supportstructure 126 that shapes the warp yarn material in the general shape ofa cylinder with the warp yarns or yarns in the material being alignedlongitudinally along the length of the substantially cylindrical supportsurface. When formed into the cylindrical shape, the warp yarn materialis advanced through the weft yarn application station 66 at apre-determined rate with the adhesive positioned on the exterior surfaceof the cylindrically configured warp yarn material. As the warp yarnmaterial passes through the weft yarn application station, a series ofweft yarns 128, as best seen in FIGS. 8, 12-15, 17 and 18) radiallylocated on a rotating drum 130 an equal distance from one another arewrapped transversely around the cylindrically configured warp yarnmaterial at a predetermined rate and the resultant laminate of warp yarnmaterial 78, adhesive scrim or lace 116 and weft yarns 128 is thenadvanced through the heating station 68 where the adhesive scrim or laceis activated so that the adhesive bonds the warp yarn material and theweft yarns. It will be appreciated that as an alternative, adhesivecould be sprayed onto the warp yarns before the weft yarns are laiddown. Immediately thereafter the material passes through the cooling oradhesive setting station 70 where the adhesive is set so as to no longerbe tacky. As the resultant fabric laminate 131 progresses from thecooling station to the take-up station 76, a cutter 132, preferably arotary cutter, longitudinally severs the cylindrical laminate and thelaminate material progressively changes from its cylindrical orientationto a generally flat orientation in the flattening station 72. At thedownstream end of the flattening station, the belt passes down andaround a drive roller 133 (FIG. 2B), that underlies the endless belt,where the belt is returned to the supply station 64 via tensioningroller 135 and idler rollers 137.

The drive roller, through its driving engagement with the endless belt,thereby advances the warp yarn material through the apparatus. Uponpassing the drive roller, the laminate material, in a preferredembodiment, is passed through a flat bed laminator 74, after which it iswrapped onto a take-up roller 136 at the take-up station which can beremoved from the apparatus when necessary or at pre-determinedintervals. FIG. 2 is another diagrammatic view looking down on theapparatus shown in FIG. 1. This view illustrates the longitudinal, ormachine direction orientation of the warp yarn material as it enters theweft yarn application station 66 and the resultant nonwoven laminatefabric product 131 extending from the weft yarn application stationtoward the take-up station 76. As best illustrated in FIGS. 4 through 7,the support structure 126 extends from the supply station through theweft yarn application station 66 to the take-up station so as to supportthe warp yarn material 78 and ultimately the nonwoven fabric laminate131 in a desired orientation for processing. The support structureincludes a horizontal beam 138 extending uninterruptedly from the supplystation 64 to the take-up station 76. The horizontal beam is coveredwith and supports a rigid foam 140 or other desirable material that willmaintain its shape and configuration over time. The foam is a rigidpolyurethane foam manufactured by Great Stuff and distributed throughHome Depot centers throughout the United States. The foam is typicallyused for insulating window casements. At the supply station, and as bestseen in FIGS. 4 and 5, the foam, which has an outer low frictioncovering 142 defines a flat upper surface and as the body of foamprogresses toward the weft yarn application station 66, the outercovering progressively transforms into a substantially cylindricalconfiguration. As seen in FIG. 6, at an intermediate location betweenthe supply station and the weft yarn application station, the outercovering of the foam is somewhat semi-cylindrical but as it reaches theweft yarn application station as seen in FIG. 7, the outer covering issubstantially cylindrical. The reverse transformation of the outercovering occurs from the weft yarn application station to the driveroller 133 for a purpose to be described later.

The supply of warp yarn material 78 is disposed on the transfer roll 90at the supply station and the yarns or fibers in the material 78 extendin parallel side-by-side relationship. A suitable braking or frictionsystem (not seen) prevents the roll 110 from rotating freely and thusoverrunning. The material is passed over an idler roller 144 onto thedriven, endless recycling Teflon® belt 124 that supports the warp yarnmaterial and advances it through the weft yarn application station. TheTeflon® belt conforms to the support structure 126 and slides over astainless steel wear plate that acts as the outer covering 142 of thefoam body 140. When the warp yarn material is first fed onto the beltingsurface as seen in FIG. 4, the yarns or fibers of the material arepositioned in parallel side-by-side relationship and extendlongitudinally of the apparatus, FIG. 4 also shows the layer of adhesivescrim or lace 116 of the material overlaid on the warp yarn material asthe material progresses onto and along the belting. As will be seen inFIG. 6, as the warp yarn material progresses through the apparatus, itis supported and carried by the Teflon® belt along the supportstructure. It initially assumes an arcuate downwardly concaveorientation and, finally, when it approaches the weft yarn applicationstation as shown in FIG. 7, it assumes a substantially cylindricalconfiguration with only a small longitudinal gap at the bottom of thecylinder.

As seen in FIG. 8, at the weft yarn application station 66, the foambody 140 and stainless steel wear plate or covering 142 are interruptedbut the Teflon® belting 124 continues through the weft yarn applicationstation and is supported by a rigid inner cylindrical ring 144 thatextends substantially the full length of the weft yarn applicationstation. The cylindrical ring 144 is almost contiguous with the foam 140and, in essence, forms a continuation of the foam body through the weftyarn application station with only a small gap existing as the Teflon®belting and warp yarn material are fed through the center of the weftyarn application station.

The weft yarn application station 66, as probably best seen in FIGS. 8and 17, includes an outer housing 146 having a front or upstream wall148 with a central circular opening 150 therethrough, a rear ordownstream wall 152 having an aligned circular opening 154 therethrough,a top wall 156, a bottom wall 158, and side walls 160. As best seen inFIG. 8, a rigid support ring 162 having a peripheral flange 164 at itsupstream end is bolted or otherwise secured to the rear wall 152 of thehousing and defines a cylindrical passage 166 through the weft yarnapplication station. An inner cylindrical surface of the support ring iscircumferentially spaced from the belting as it extends through the weftyarn application station. The support ring carries at longitudinallyspaced locations on its outer surface the inner races of large diameterthin section ball bearings 168 such as of the type provided by KaydonCorp. of Sumter, S.C. Outer races of the ball bearings respectivelysupport another cylindrical body 170 that forms the inner cylindricalwall of the rotating drum. The inner cylindrical wall of the rotatingdrum supports a front radial wall 172 at the upstream end of the drumand rear radial wall 174 at the downstream end of the drum, and theradial walls support an outer cylindrical wall 176 of the drum. The rearradial wall 174 has concentric ring-like portions defining an inner ringplate 175 and an outer ring plate 177. The inner ring plate is securedby fasteners to the ends of the inner cylindrical wall 170 and the outerring plate is secured with fasteners to an annular flange 179 secured tothe inner cylindrical wall 170, as best seen in FIG. 14. A variablespeed electric motor 178, serving as power means for the weft yarnapplication station, is mounted on the upstream face of the front wall148 of the housing and has a drive shaft 180 that extends into theinterior of the housing and supports a drive pulley 182 that is alignedwith one of the ball bearings 168. The inner cylindrical wall 170supports a pulley 186 around which a drive belt 188 extends so as tooperably interconnect the drum with the drive pulley 182 of the electricmotor. Energization of the electric motor thereby rotates the drum atvariably selected speeds. The details of the mounting of the ballbearing and drive belt is probably best seen in the enlarged view inFIG. 10.

The rear or downstream radial wall 174 of the rotating drum consists ofa circular plate having a plurality (in the disclosed embodiment six) ofcircumferentially spaced circular openings 190 therethrough. Aperipheral seat 192 passes around each opening so that a disk-likeclosure plate 194 can be seated in the seat to selectively close theopening. Thumb screw fasteners 196 secure the disk-like closure platesto the rear wall of the drum for easy attachment and removal. Thisrelationship is probably best illustrated in FIGS. 9, 14, 15 and 17.Each disk-like closure plate 194 has an eyelet 198 secured thereto atits geometric center so that the eyelet is positioned on the inner sideof the disk. The eyelet serves as a guide for the weft yarn material128, as will be explained hereafter. A plurality of source supplies ofweft yarn material are provided in the form of spools 200 of suchmaterial and are removably mounted on the inner surface of the frontwall 172 of the rotating drum, again in circumferentially spacedrelationship and alignment with the circular openings 190 in the rearwall of the drum. It should be appreciated that the number of spools ofweft yarn material could vary and while the disclosed embodiment showssix such spools, more or less could be used, in a preferred embodiment,twelve such spools are used. The weft yarn material is extended from aspool 200 to the eyelet 198 on the associated closure disk 194 and thenpassed radially inwardly through a gap 202 between the closure disk andthe front wall of the drum as best seen in FIG. 15. Associated with eachclosure disk and in radial alignment therewith is a tensioner 204 forcontrolling the tension of the weft yarn material mounted on thedownstream side of the rear wall 174.

The tensioner 204 as best seen in FIGS. 14, 18 and 31 consists of athreaded rod 206 projecting downstream of the machine and having adisk-like base 208. A collar 210 is slidably disposed on the rod andalso has a disk-like base in confronting relationship with the disk-likebase 212 of the rod. A coil spring 214 is concentrically mounted on therod and in engagement with the collar 210 at one end and in engagementwith a threaded nut 216 at the opposite end so that the nut can bethreaded onto the rod and positioned at any selected longitudinalposition to vary the compressive strength of the coil spring. The weftyarn material 128 passes between the base of the rod and the base of thecollar and is allowed to slide therebetween but in frictional engagementtherewith. The frictional drag on the weft yarn material is regulated bythe compressive strength of the spring.

Immediately adjacent to the tensioner 204 and in radial alignmenttherewith at the innermost edge of the rear wall 174 of the drum 136 isa guide pin 218 that also projects downstream of the machine and aroundwhich the weft yarn material extends. The guide pin is positionedimmediately adjacent to the warp yarn material 78, for example, at a gapof about 0.015 inches, though other gaps could be used. The guide pinthereby allows the weft yarn 128 to be very accurately applied acrossthe warp yarn material as the drum is rotated in a manner to bedescribed in more detail hereafter.

As probably best seen in FIG. 18, a plurality of leveling plates 220 ofgenerally L-shaped cross-section are mounted on the downstream face ofthe rear wall 174 of the rotating drum immediately adjacent to anassociated tensioner 204 and guide pin 218 and positioned to the rightor in a clockwise direction from the tensioner and guide pin whenlooking upstream. The leveling plate is mounted a distance approximatelyequal to the thickness of the weft yarns 128 from the adhesive outersurface of the warp yarn material 78 so as to assure a uniform levelwrap of the weft yarn material onto the adhesive scrim or lace of thewarp yarn material.

An alternate guide pin in the form of a leveling block 222 isillustrated in FIGS. 30 through 36 It will there be seen that theleveling block is positioned immediately adjacent to an associatedtensioner 204 which serves both to guide the weft yarn 128 as it is laiddown on the warp yarn material 78 and also to assure that the previouswraps of weft yarn are in a single layer and packed together as desired.The block 222 provides significant control over the lay down of the weftyarn material and provides for accurate placement of the yarns relativeto one another. The weft yarns can be packed very densely up to 140,36/1 cotton count yarns per inch or they can be placed accurately withno more than a ten thousandths of an inch difference in the position ofone yarn and the position of the next adjacent yarn.

The leveling block 222 as best seen in FIG. 36 is generally L-shaped intransverse cross-section and pivotally mounted to a ring block 224(which replaces the inner ring plate 175 described previously) on theinner periphery of the rear wall 174 of the rotating drum 130 with apivot assembly. The pivot assembly as best seen in FIGS. 30 and 31includes a pivot shaft 226 that is keyed to the leveling block andsecured thereto with a cap screw 228 with the pivot shaft beingrotatably mounted on a pair of ball bearings 230 mounted within the ringblock. The innermost end of the pivot shaft also has a cap screw 232secured therein which retains a compression spring 234 between the endcap and an abutment surface 236 within the ring block. The compressiveforce of the compression spring can be regulated with the cap screw andserves to operably draw the leveling block against a low friction washer238 to adjust the ease with which the leveling block is allowed to pivotwith the pivot shaft.

A coil spring 240 anchored to the rear wall 174 of the rotating drum 130and to the leveling block 222 biases the opposite end of the blockagainst the underlying previously wrapped weft yarn material 128. Thiskeeps the wraps of weft yarn material in one uniform level which isdesired for the finished nonwoven fabric product. The leveling block hastwo legs 242 and 244 which define a groove 246 at their juncture withthe groove confining and controlling a segment of the weft yarn material128 as it is transferred from the associated and adjacent tensioner 204to the surface of the warp yarn material 78 in a controlled manner. Ofcourse, when the leveling blocks are used, the previously describedleveling plates 220 are not necessary.

An adjustable spacer 248 is mounted on the leveling block 222 andfunctions to selectively adjust the spacing between the leveling blockand the ring block 224 (FIGS. 30 and 31) so that the groove 246 in theleveling block can be aligned with the tensioner 204 whereby the weftyarns pass in a straight line through the tensioner and the groove inthe leveling block before being applied to the adhesive scrim. Theadjustable spacer 248, as probably best seen in FIGS. 30, 35 and 36,includes an L-shaped wedge base 250 having a short leg 252 with acircular passage 254 therethrough and a long leg 256 having a slot 258in its free end so as to bifurcate the long leg thereby defining a pairof straddling arms 262. The long leg is tapered in cross-section so thatit is thicker at the end adjacent to the short leg 252 and thinner atits free end 260. The L-shaped base is secured to an end of the levelingblock 222 with an adjustable cap screw 264 that passes through thepassage 254 in the short leg such that the short leg is captured betweenthe head 266 of the screw and a fixed washer 268 on the screw. The screwis threadably received in a threaded hole 270 in the end of the levelingblock and is adjustable therein so that as the screw is advanced into orbacked out of the threaded hole in the leveling block, the L-shaped baseis slidably moved relative to the pivot shaft 226. The slot 258 in thelong leg straddles the pivot shaft so that the arms 262 are positionedabove and below the pivot shaft. Sliding movement of the L-shaped armalong the length of the long leg 256 between the leveling block and thering block causes the spacing between the leveling block and the ringblock to be adjusted as the cap screw 264 is moved into or out of thethreaded hole. The L-shaped base is preferably made of a low frictionmaterial that interfaces with the low friction washer 238 previouslydescribed so that the leveling block freely pivots relative to the ringblock as desired.

The heating or adhesive activating station 68 consists of a steel orother heat transmitting cylindrical core 272 that is positionedinteriorly of the belt 124 immediately downstream from the weft yarnmaterial application station 66 and forms an axial extension of therigid cylindrical ring 162 in the weft yarn application station.Resistive heat elements 274 are circumferentially positioned around thesteel core 272 with the resistive heat elements connected to anelectrical source by wiring 276 as possibly best seen in FIGS. 8 and 10,which passes through the cylindrical ring support in the weft yarnapplication station and outwardly of the apparatus through a circularaperture 278 therein so that it can be plugged into an electrical powersource in a conventional manner. When an electrical current is appliedto the resistive elements, the metal core 272 is heated therebyradiating heat outwardly through the warp yarn material, the adhesivescrim or lace of the warp yarn material, and the overlying layer of weftyarn material. The heat is controlled to sufficiently activate theadhesive in the adhesive scrim to bond the warp and weft yarns together.In addition to the heating and cooling means described herein, theskilled artisan can select other heating and cooling means, e.g., steamheat and cooling water mist, could be employed.

As the composite material 131 of bonded warp and weft yarns is moveddownstream, it next encounters the cooling or adhesive setting station70 which, again, includes a steel or other heat conductive cylinder 280which immediately underlies the belt 124. A heat transfer system 282interiorly of the cylinder 280 uses circulating coolant from inlet andoutlet tubes 284, respectively, in a conventional manner to remove heatfrom the composite material. The coolant transfer tubes which are seenin FIG. 19, for example, are connected to the heat transfer system sothat a continuous supply of coolant fluid can be circulated through thecooling station to set the adhesive of the scrim or lace therebysecurely bonding the warp and weft yarn material.

As the composite fabric material 131 leaves the cooling station 70 andis moved further downstream, it engages the fabric cutter 132 that isconventional and is mounted on a bracket 286 immediately beneath thefoam support 140. The cutter serves to sever the composite material 131of warp and weft yarn material along its length as it is moved along theapparatus. Heat or ultrasonic means (not shown) can also be used to fusethe severed edges of the fabric material as it is being cut.

As the composite fabric material progresses further downstream afterbeing cut, it is flattened out as the support structure 126 transgressesfrom a cylindrical configuration to a flat configuration in theflattening station 72. Accordingly, as the nonwoven fabric materialreaches the drive roller 133 and then passes to the take-up station 76,it has been flattened on the belt 124 and is wrapped around the take-uproll 136 until a desired amount of fabric material has been accumulated.The take-up roll can then be removed from the machine and replaced withanother take-up roller to continue the process.

The resulting nonwoven fabric has both warp and weft yarns, secured byadhesive which contacts only a portion of the individual yarns, i.e., byyarn to yarn, or point to point contact. No yarns in the product areintentionally coated completely with adhesive. This factor preserves thefeel of the nonwoven fabric as being more akin to a woven fabric. Thisnonwoven fabric material is another especially preferred embodiment ofthe present invention.

To further describe one preferred nonwoven fabric manufacturing methodof the invention and the operation of the apparatus therefor, a supplyroll 90 of warp yarn material that was prepared in the warp yarnmaterial manufacturing unit 82 is mounted in the supply station 64 andthe warp yarn materials pulled through the apparatus to the take-upstation where it is secured to the take-up roll 136. The drive roller133 is rotatively driven by a motor (not shown) at the same speed as thetransfer belt 124 and the motor is controlled by a control system in box302 (FIGS. 1-3) that also serves as the control system for the motor 178at the weft yarn application station 66, the heating station 68 and thecooling station 70. To begin manufacture of the nonwoven fabric 131,after the warp yarns have been aligned and adhesive has been applied tothem, or in the alternative to a nonwoven substrate in the warp yarnmaterial manufacturing unit 82, to create the warp yarn material, thedrive roller 133 and transfer belt 124 are driven in conjunction withthe take-up roll 136. The Teflon® belt 124 supports and moves the warpyarn material along the length of the apparatus. A braking force (notshown) is applied to the supply roll of the warp yarn material tofacilitate regulating the tension in the warp yarn material and avoidoverruns. The rotating drum 130 in the weft yarn application station isnext activated so as to rotate in a clockwise direction as viewedupstream in FIGS. 17 and 18. Before advancing the warp yarns and beforerotating the drum, the strands of weft yarn material mounted in the drumare threaded through the associated eyelets 198, the tensioners 204 andaround the guide pins 218 and initially taped to the warp yarn material78. It will, therefore, be appreciated that when the drum is rotated inthe clockwise direction, the various strands of weft yarn material 128are wrapped around the warp yarn material, which is simultaneously beingmoved linearly through the weft yarn application station 66 so that thevarious strands of weft yarn material are wrapped about the warp yarnmaterial in adjacent relationship. As will be appreciated, by varyingthe rate of rotation of the drum relative to the linear speed of thewarp yarn material passing through the drum, the spacing of the weftyarn strands can be regulated so that the strands are either positionedin closely packed contiguous relationship or slightly spaced with thespacing being variable but precise relative to one another dependingupon the relative speeds of the rotating drum and drive roll andtransfer belt which advances the transfer belt and the warp yarnmaterial linearly through the drum. Of course, the greater the ratio oflinear speed of warp yarn material to the rotating speed of the drum,the greater the spacing between wraps of weft yarn strands.

As will also be appreciated, since the warp yarn material is movinglinearly in a machine direction, as the weft yarns are wrapped therearound, the weft yarns are not wrapped perfectly perpendicular to thewarp yarns or fibers in the warp yarn material even though they aresubstantially so. Again, as the ratio of the linear speed of the warpyarn material to the rotative speed of the drum increases, the angle ofwrap of the weft yarn material relative to the length of the warp yarnsor fibers decreases. The angle of wrap might vary anywhere up toslightly more than about 89.7 degrees depending upon the relativedifferential in speeds. In other words, when slowing the linear speed ofthe warp yarn material relative to the rotative speed of the drum, theyarns can be wrapped closely together and substantially perpendicular tothe warp yarns or fibers in the warp yarn material (i.e., approaching 90degrees) but as the linear speed of the warp yarn material is increasedwithout increasing the rotating speed of the drum, the angle of wrapdecreases down to, for example, about 80-85 degrees. The angle of wrapis the angle between the longitudinal axis of the machine and thetransverse direction of the weft yarn material.

As mentioned previously, after the weft yarn material is wrapped aboutthe adhesive scrim and the underlying warp yarns or fibers of the warpyarn material, the combined materials pass through a heating station 68where the adhesive is activated to a tacky state such that the warp andweft yarn material are adhesively bonded or joined together. As thematerial progresses further downstream, it passes through a coolingstation 70 where the adhesive is set so as to remove the tacky or stickynature of the adhesive but yet the warp and the weft yarns are bondedinto a nonwoven fabric as desired. Further movement of the warp and weftmaterial along the length of the machine causes the cylindricallywrapped weft yarns to be cut by the cutter 132 thereby forming a web ofnonwoven fabric material 131 which is flattened out as it progressestoward the drive roller, a flat bed laminator 74 (if used), andultimately the take-up roll 136 (or sheeter, not shown), by theprogressively flattening nature of the support structure 126 on whichthe material is guided. The material is wrapped around the take-up rollat the take-up station which can be removed from the machine when adesired amount of nonwoven fabric material is wrapped thereon.

The adhesive scrim or lace 116 of the warp yarn material 78 could comein numerous forms but in a preferred embodiment it is a web of adhesivestrands which have been secured together randomly providing gapstherebetween. A suitable adhesive web is manufactured by Bostic Companyof Middleton, Mass. Accordingly, when the adhesive scrim is activated atthe heating station, the adhesive does not cover the entire surface areaof the warp and weft yarn material but rather preferably has a basisweight that is about 5-20% of the total weight of the structure. Theamount of adhesive laid down has a direct bearing on the softness andhand of the nonwoven fabric material manufactured with the abovedescribed apparatus and, of course, this is a variable that iscontrolled with the type of scrim or other adhesive material used.

Another type of adhesive material that could be used is a meltblownadhesive. A meltblown adhesive web could be purchased, or a meltblownapplicator could be used to blow the adhesive onto the adhesive supportroll of the adhesive applicator for lamination onto the aligned warpyarns or the meltblown adhesive could be blown directly onto the warpyarns. The advantage of a meltblown adhesive may be the uniformity ofthe web at the low density of adhesive basis weight. Since meltblownfibers are micro denier fibers, a low density, and very uniform web canbe created for bonding the warp yarns to the weft yarns of the nonwoven.Uniformity of the adhesive web may enhance the appearance of thenonwoven.

As mentioned previously, by varying the speed of rotation of the drum130 relative to the linear speed of the belt 124, the wraps of weft yarnmaterial can either be positioned immediately adjacent and contiguouswith each other or in spaced relationship. This is illustrated, forexample, in FIGS. 23 and 24, respectively. Warp yarns 84 as illustratedin each embodiment are positioned contiguous with each other but thespacing of the wraps of weft yarn 128 is varied. FIG. 25 shows an evengreater spacing of the weft yarns 128 relative to the warp yarns 84 andit should be appreciated, even though it is not evident in the drawings,that the greater the spacing of the weft yarn wraps, the smaller theangle of wrap the weft yarns make with the longitudinal axis of the warpyarns. In other words, as the weft yarns are wrapped closer and closertogether, the angle of wrap of the weft yarn increases to approach 90degrees, but as the spacing of the weft yarns increase, the anglediminishes down to, for example, approximately 80-85 degrees. FIG. 27 isa diagrammatic view illustrating the adhesive bond between the warp 84and weft 128 yarns, while FIG. 28 is a diagrammatic view illustratinghow the adhesive in the scrim 116 is applied only to the radiallyoutermost surface of the warp yarns 84.

FIG. 29 illustrates still another embodiment of a fabric that can bemanufactured with the apparatus of the present invention and wherein theweft yarn material 128 is of a smaller denier or diameter than the warpyarns 84 It will be appreciated that the warp yarns could also be of asmaller denier relative to the weft yarns. Moreover, mixtures of weftyarns (not shown), for example yarns of various types (synthetic,natural, yarn-substitutes) and/or yarns of various deniers, can beapplied as weft yarns using this apparatus, resulting in nonwoven fabricmaterials having particularly interesting and unique properties.

Another preferred version of the XD apparatus is shown in FIGS. 60through 70, and includes an elongated in-line framework 62′ including awarp yarn material supply station 64′, a weft yarn application station66′, a heating station 68′, a cooling station 70′, a flattening station72′, and a take-up station 76′. From the take-up station, the compositenonwoven fabric of this invention can either be used directly, forinstance as a light filtering medium, or it can be pressure laminatedinto a high strength composite fabric, suitable for use under extremeconditions, e.g., as sail cloth fabric. As shown in FIGS. 60 and 62, awarp yarn material 78′ is provided on a supply roll 80′ at the warp yarnmaterial supply station 64′. Once in place at the supply station 64′ ofthe apparatus of the present invention the warp yarn material 78′ ispassed on an endless, recycling transfer belt 124′, preferably of PTFE(Teflon®). A series of bars and folding points (not shown) convert theflat sheet of warp yarn material and the belt into a curved orcylindrical shape. This folding box equipment is known in the art, andonce the warp yarn material has the general shape of a cylinder, withthe adhesive layer on the outside or exposed surface, the warp yarns areready to be over wrapped with the weft yarn material.

Once formed into a cylindrical shape, the warp yarn material is advancedthrough the weft yarn application station 66′ at a pre-determined ratewith the warp yarn adhesive film positioned on the exterior surface ofthe cylindrically configured warp yarn material. As the warp yarnmaterial passes through the weft yarn application station, a series ofweft yarns 128′ radially located on a rotating drum 130′ an equaldistance from one another are wrapped transversely around thecylindrically configured warp yarn material at a predetermined rate andthe resultant composite structure of warp yarn material 78′, adhesivefilm 116′ and weft yarns 128′ is then advanced through the heatingstation 68′ where the adhesive film is melted so that the adhesive willbond the warp yarn material and the weft yarns.

Immediately thereafter, the composite material passes through thecooling or adhesive setting station 70′ where the adhesive is set so asto no longer be tacky. The bonded fabric composite 131′ progresses fromthe cooling station to the take-up station 76′, a cutter 132′,preferably a rotary cutter, longitudinally severs the cylindricalcomposite fabric material and the cut composite fabric materialprogressively changes from its cylindrical orientation, back to agenerally flat orientation in the flattening station 72′. At thedownstream end of the flattening station, the belt passes down andaround a drive roller 133′ that underlies the endless belt, where thebelt is returned to the supply station 64′ via tensioning roller 135′and idler rollers 137′. The drive roller, through its driving engagementwith the endless belt, thereby advances the warp yarn material throughthe apparatus.

FIG. 63 is another diagrammatic view looking down on the apparatus shownin FIG. 62. This view illustrates the longitudinal, or machine directionorientation of the warp yarn material as it enters the weft yarnapplication station 66′ and the resultant nonwoven composite fabricproduct 131′ extending from the weft yarn application station toward thetake-up station 76′.

The supply of warp yarn material 78′ is disposed on the transfer roll 90at the supply station and the yarns or fibers in the material 78′ extendin parallel side-by-side relationship. A suitable braking or frictionsystem (not shown) prevents the roll 110′ from rotating freely and thusoverrunning. The =material is passed over an idler roller 144′ onto thedriven, endless recycling PTFE (Teflon®) belt 124 that supports the warpyarn material and advances it through the weft yarn application station.The PTFE (Teflon®) belt conforms to the support structure 126′ andslides over a stainless steel wear plate.

As seen in FIG. 63, at the weft yarn application station 66′, the PTFE(Teflon®) belting 124′ continues through the weft yarn applicationstation and is supported by a rigid inner cylindrical ring 144′ thatextends substantially the full length of the weft yarn applicationstation. FIG. 64 illustrates the weft yarn application station 66′ whichincludes an outer housing 146′ having a rear or downstream wall 152′having an aligned circular opening 154′ therethrough, a top wall 156′, abottom wall 158′, and side walls 160′. A rigid support ring 162′ havinga peripheral flange 164′ at its upstream end is bolted or otherwisesecured to the rear wall 152′ of the housing and defines a cylindricalpassage 166′ through the weft yarn application station. An innercylindrical surface of the support ring is circumferentially spaced fromthe belting as it extends through the weft yarn application station. Thesupport ring carries at longitudinally spaced locations on its outersurface the inner races of large diameter thin section ball bearings168′ such as of the type provided by Kaydon Corp. of Sumter, S.C. Outerraces of the ball bearings respectively support another cylindrical body170′ that forms the inner cylindrical wall of the rotating drum. Theinner cylindrical wall of the rotating drum supports a front radial wall172′ at the upstream end of the drum and radial wheel 194′ at thedownstream end of the drum, and the radial walls support an outercylindrical wall 176′ of the drum. The radial wheel 194′ has guide posts195′ on the outer edges for delivering the weft yarns to the warp ring.The innermost portion of the radial wheel terminates at the conicalaligner 200, which has a radiused, curved or sloped surface. The conicalaligner 200 guides the weft yarns into a substantially perpendicularalignment with the warp yarns.

A variable speed electric motor 178′, serving as power means for theweft yarn application station, is mounted on the upstream face of thefront wall 148′ of the housing and has a drive shaft 180′ that extendsinto the interior of the housing and supports a drive pulley 182′ thatis aligned with one of the ball bearings 168′. The inner cylindricalwall 170′ supports a pulley 186′ around which a drive belt 188′ extendsso as to operably interconnect the drum with the drive pulley 182′ ofthe electric motor. Energization of the electric motor thereby rotatesthe drum at variably selected speeds. The details of the mounting of theball bearing and drive belt is probably best seen in the enlarged viewin FIG. 65.

A plurality of source supplies of weft yarn material are provided in theform of spools 206′ of such material and are removably mounted on theinner surface of the front wall 172′ of the rotating drum, again incircumferentially spaced relationship and alignment with the circularopenings 190′ in the rear wall of the drum. It should be appreciatedthat the number of spools of weft yarn material could vary and while thedisclosed embodiment shows six such spools, more or less could be used,in a preferred embodiment, twelve such spools are used. The weft yarnmaterial is extended from a spool 206′ to the eyelet 198′ on disk 194′and then passed radially inwardly down the face of disk 194′ to anothereyelet at the base of disk 194′.

As the weft yarn application drum rotates, the weft yarns are deliveredthrough guides 204′ on disk 194′, and the yarns slip down the curvedslope of the conical aligner 200, by which each yarn is delivered to thewarp in a substantially perpendicular alignment. FIGS. 69 and 70 bestillustrate the conical aligner of the present invention. As shown inFIG. 69 in particular, the conical aligner 200 is a stationary device,with a surface angle or slope which faces the direction of travel of thewarp yarn materials. The weft yarns are delivered to the surface of theconical aligner by rotatory pulleys operating in conjunction with therotating drum. As with the previously described XD embodiment, mixturesof weft yarns (not shown), for example yarns of various types(synthetic, natural, yarn-substitutes) and/or yarns of various deniers,can be applied as weft yarns using this apparatus, resulting in nonwovenfabric materials having particularly interesting and unique properties.The individual weft yarns are each delivered to substantially the samespot on the sloped surface of the conical aligner. They fall down thesloped surface, and are forced, one after the other, down into a tightspacing on the surface of the adhesive coated warp yarns. FIG. 70 showsa perspective view of the application of weft yarns, in a wide spacingmanner, to the warp yarns. FIGS. 69 and 70 are perspective views showingthe conical aligner 200 from the right and left sides respectively. Oncethe weft yarns have been applied to the warp yarn material, the adhesivebetween the yarns must be heated and cooled to form a nonwoven fabric.These steps are conducted in the next part of the apparatus as discussedbelow.

The adhesive heating station 68′ consists of a steel or other heattransmitting cylindrical core 272′ that is positioned interiorly of thebelt 124′ immediately downstream from the weft yarn material applicationstation 66′ and forms an axial extension of the rigid cylindrical ring162′ in the weft yarn application station. Resistive heat elements 274′are circumferentially positioned around the steel core 272′ with theresistive heat elements connected to an electrical source by wiring 276′as possibly best seen in FIGS. 67 and 69, which passes through thecylindrical ring support in the weft yarn application station andoutwardly of the apparatus through a circular aperture 278′ therein sothat it can be plugged into an electrical power source in a conventionalmanner. When an electrical current is applied to the resistive elements,the metal core 272′ is heated thereby radiating heat outwardly throughthe warp yarn material, the adhesive on the warp yarn material, and theoverlying layer of weft yarn material. The heat is controlled tosufficiently melt the adhesive to bond the warp and weft yarns together.

As the composite fabric material 131′ of bonded warp and weft yarns ismoved downstream, it next encounters the cooling or adhesive settingstation 70 which, again, includes a steel or other heat conductivecylinder 280′ which immediately underlies the belt 124′. A heat transfersystem 282′ interiorly of the cylinder 280′ uses circulating coolant(e.g., cold water) from inlet and outlet tubes 284′, respectively, in aconventional manner to remove heat from the composite fabric material.The coolant transfer tubes (not shown) are connected to the heattransfer system so that a continuous supply of coolant fluid can becirculated through the cooling station to set the adhesive therebysecurely bonding the warp and weft yarn material.

As the composite fabric material 131′ leaves the cooling station 70′ andis moved further downstream, it engages the fabric cutter 132′ that isconventional and is mounted on a bracket 286′. The cutter serves tosever the composite fabric material 131′ along its length as it is movedalong the apparatus.

As the material progresses further downstream after being cut, it isflattened out as the support structure 126′ transgresses from acylindrical configuration to a flat configuration in the flatteningstation 72′. Accordingly, as the nonwoven composite fabric materialreaches the drive roller 133′ and then passes to the take-up station76′, it has been flattened on the belt 124′ and is wrapped around thetake-up roll 136′ until a desired amount of fabric material has beenaccumulated. The take-up roller can then be removed from the machine andreplaced with another take-up roller to continue the process. Ifdesired, the combined warp and weft yarn material formed on either ofthe XD apparatus described above can be reused as a substrate material.An adhesive material would be required for further processing withadditional layers of weft yarn materials, but composite structures canbe formed using the apparatus described herein.

Pressure Lamination Apparatus and Nonwoven Fabrics Formed Thereby

If desired, the bond between the warp yarns and weft yarns can be mademore intimate, for example by heating and cooling the product underpressure, e.g., by a lamination apparatus. One embodiment of a flat bedlaminator 74 as illustrated in FIG. 1B, may be positioned between thedrive roller 133 and the take-up roller 136. The flat bed laminator maybe of a conventional type manufactured by Reliant of Great Britain andserves to further enhance the above described heating and coolingstations 68 and 70 respectively. The flat bed laminator reheats and thencools the nonwoven fabric 131 to set the adhesive in a flat as opposedto cylindrical configuration which is sometimes advantageous dependingupon the type of yarns utilized and further enhances the bond as well.

A diagrammatic representation of a flat bed laminator of the type thatmight be employed in the apparatus of the present invention is shown inFIG. 1B. It will there be appreciated that the laminator is disposed atthe downstream end of the apparatus in a position to receive thelaminated fabric material 131 of the present invention. The laminatorincludes a housing 288 in which are disposed a pair of driven pressurebelts 290 between which the laminate passes and is driven through aheating/cooling system 292 with a first segment of the system comprisinga heater 294 with conventional heating coils or the like above and belowthe fabric and the second segment of the system being a cooler 296 withconventional cooling lines above and below the fabric. Accordingly, asthe fabric passes through the heating/cooling system the adhesive isinitially reactivated or remelted with the laminate in a flatorientation and shortly thereafter the laminate is cooled to thereby setthe adhesive. Pressure is applied to the laminate by the pressure belts290 as it advances through the heating/cooling system from above andbelow the laminate so that the cross-section of the laminate changesfrom the arrangement illustrated in FIG. 41 where the weft yarns arelightly bonded to the warp yarns to an orientation as shown in FIG. 42where the weft yarns are further embedded in the adhesive and,therefore, more tightly adhered to the warp yarns.

After leaving the cooler 296, the fabric passes around the end of thelower pressure belt 290 and then is directed upstream through a pair ofidler rollers 300 and onto the take-up roll 136 at the downstream end ofthe manufacturing apparatus.

An especially preferred high pressure lamination apparatus 400 isillustrated in FIGS. 71 through 77. The laminator 400 comprises ahousing or frame in which a pressure box is mounted. The pressure boxcomprises two spaced apart pressure sections, an upper section and alower section, wherein the space formed between the two pressuresections defines the lamination section. Two counter rotating drivebelts, an upper drive belt and a lower drive belt, are rotatably mountedin the housing or frame, and the belts contact one another and arepulled through the lamination section by drive rollers mounted at theoutlet end. A pressure generator is used to supplying air (or otherfluid medium—liquid or gas) pressure to the upper and lower sections ofthe pressure box for compressing substrate materials carried between thetwo drive belts. Pressure is maintained because the box has pressureseals all around the points of contact with the belt. In the rectangularbox of the current preferred embodiment, side seals are provided on thesides of both the upper and lower sections of the pressure box. Inletand outlet seals are also provided on the upper and lower sections ofthe pressure box, ensuring that the desired diaphragm effect can becreated therein. When pressurized, the apparatus caused the pressurelamination of substrates situated between the two belts.

Referring to FIG. 71, a number of the essential components of thepreferred pressure box 401 used in the pressure laminator of the presentinvention are shown in cross-section. As illustrated, two rotatablebelts, top belt 402 and bottom belt 404, mounted on a plurality ofsupport rollers (top—410, 420, 430; bottom—510, 520, 530), are pulledthrough the pressure box 401, between the upper section 412 and thelower section 414, entering at the inlet end 416 and exiting at theoutlet end 418, by their respective drive rollers 550 (top) and 650(bottom).

Alignment of the two rotating belts 402 and 404, is maintained by anelectric alignment system comprising an alignment carriage 700,alignment pivot 710, electric alignment servo 720 and electric alignmenteye 730. If either of the belts move out of alignment, the electric eye730 detects the same and activates the alignment servo, which causes thebelt to be adjusted as necessary by lateral movement of the alignmentcarriage 700.

Eight spaced apart radiant heat bars (310A, 310B, 310C, 310D . . . 310H)are shown at the inlet end 416 of pressure box 401 and eight spacedapart cooling bars (320A, 320B, 320C, 320D . . . 320H) are shown at theoutlet end 418 of pressure box 401. Four of the heat bars are rigidlymounted in the lower section 414 of the pressure box 401, namely heatbars 310A, 310C, 310E and 310G. The other four radiant heat bars (310B,310D, 310F and 310H) are flexibly mounted such that they float above theupper belt, permitting materials of varied thickness to pass thereunder. Four of the cooling bars are rigidly mounted in the lower section414 of the pressure box 401, namely cooling bars 320A, 320C, 320E and320G. The other four cooling bars (320B, 320D, 320F and 320H) areflexibly mounted such that they float above the upper belt, permittingmaterials of varied thickness to pass there under.

As illustrated, the plurality of heating and cooling bars are preferablyarranged in a staggered configuration. Thus, the substrate is heatedfrom below, then above, then below, etc., and the cooling isaccomplished in the same manner; the substrate is cooled from below,then above, then below, etc. This arrangement permits rapid and uniformheating, as well as rapid and uniform cooling of the substrate materialsbeing laminated in the pressure laminator. The uniformity of heating andcooling under pressure leads to improved physical characteristics of theresulting laminates. In the case of nonwoven fabrics laminated in thismanner, shrinkage of the fabrics is held to a minimum and the resultinglaminated material has the appearance and feel of a woven fabric.

In the preferred embodiment, at least 75 percent of the belt width isheated and cooled by these elements. For example, on a 29 inch widebelt, the central 22 inches are heated and cooled. On a 76 inch widebelt, the central 60 inches would be heated and cooled. The ReliantER177A heat bars (England) are each provided with a thermocouple tomeasure the temperature delivered to the belts. The cooling bars areeach provided with water fed cooling pipes.

The thickness of the PTFE impregnated fiberglass belt can be modified asdesired, and depends on the nature of the materials being laminated andthe desired operating speed in feet per minute (fpm). For laminatingnonwoven fabrics, a belt thickness ranging from 2 to 20 mil, preferably5 to 15 mil has been found satisfactory. Belts of 14 mil thickness havebeen operated at 5 fpm, with a temperature of 380° F. being delivered tothe substrates. Belts of 5 mil thickness have been operated at 12 fpm,with a temperature of 380° F. being delivered to the substrates. Optimumbelt speeds of 50, 60, 70 . . . 100 fpm can be achieved by modificationof the belt thickness and/or composition. The optimum belt speed fornonwoven fabric lamination is currently believed to be 60-70 fpm.Another way in which to achieve higher speeds is to simply increase thesize of the laminator apparatus. The current preferred apparatus has alength of about 4 feet. Increasing the size from 2 times to 10 timeswould allow for faster operating speeds.

During the lamination process the substrate material may create acounter-pressure as any entrapped air in the substrates expands. To dealwith this counter-pressure, at least one (or both) of the PTFE (Teflon®)impregnated fiberglass drive belts used in the pressure laminator of thepresent invention can be modified on the outside edges, to comprise athick (about 0.125 inch) porous glass fiber mat (not shown). This porousglass fiber mat allows the expanded air from the heated laminate toescape via this sideways (transverse) porosity.

FIG. 72 illustrates in cross-section, one view of pressure box 1,showing in particular the air pressure feed line 600, and the preferredpoints of contact thereof 602 and 604 with the upper section 412 andlower section 414 of the pressure box, respectively. The pressure box isadvantageously made out of metal, such as aluminum (from 2 to 5 inchesthick) and is held together by a plurality of threaded steel rods andnuts 606 and 608. As shown in FIG. 72, the heating and cooling barslocated in the lower section 414 of the pressure box are locked in placeat each end by a fixed bracket 610. The heating an cooling bars locatedin the upper section 412 of the pressure box ride on a pin bracket mount612, which allows upward motion of the bars, while gravity keeps thebars resting on the upper belt A plurality of cooling water lines, inlet614 and outlet 616 are also shown in this illustration. The electricalheating wires (not shown) are provided in a manner similar to the waterlines.

FIG. 73 illustrates a top view of the interior of the upper section 412of the pressure box 401, showing the currently preferred arrangement ofthe upper heating bars (310B, 310D, 310F and 310H) and cooling bars(320B, 320D, 320F and 320H). The pressurized box 401 is held together bysteel bars 700 mounted to the threaded rods 706 shown in the fourcorners. Not shown in this illustration are the nuts that threadthereon. The sides 402 of the housing or frame, to which the steel barsand all rollers and controls are mounted, are also shown in this figure.

FIG. 74 illustrates, the pin bracket 812 for the upper section,vertically displaceable, heating and cooling bars. As illustrated, thepin bracket comprises a steel mounting bracket 800, fixed at one end tothe aluminum side wall of the upper section 412 of the pressure box. Aslot (not shown) is provided near the opposite end of bracket 800,through which a post 810 rides. The post 810 is mounted to the top ofthe heating or cooling bar at one end and capped at the opposite end812, thereby limiting the vertical displacement distance of the heatingand cooling bars. The bracket for the lower section heating and coolingbars 820 is also a steel bracket, but it is rigidly attached to both theheating and cooling bars and the aluminum side wall of the lower section414 of the pressure box.

A suitable inlet and side pressure seal 850 is illustrated in FIG. 74and illustrated in greater detail in FIG. 75. This seal is formed from ahigh temper curved aluminum slat 700 (0.008×1⅜″) sandwiched between 2mil PTFE (Teflon®) tape 710 on the upper side and 10 mil ultrahighmolecular weight polyethylene tape 720 on the bottom side. The seal isheld in place by a steel bracket 870.

As illustrated in FIGS. 76 and 77, it has been discovered that thealuminum pressure seal taught in FIG. 74 can be simplified, such thatthe side and inlet pressure seals consist predominantly of the curvedaluminum slat 700 as previously described. The ultrahigh molecularweight polyethylene tape can be omitted and the PTFE tape can beomitted, except in the corners 770 of the pressure box, where the tapesstill prove useful. This improved side seal and inlet pressure seal isbest illustrated in FIG. 76.

The inlet and outlet pressure seals are best illustrated in FIG. 76. Inaddition to the curved aluminum slat 700, the belt side of the aluminumslat is coated with 5 mil PTFE (Teflon®) fiberglass cloth 900, whichextends beyond the end of the aluminum seal and mounts to the inside ofthe pressure box frame. This exit seal design keeps the drive belt frombinding on the aluminum slat.

In use, the combined composite fabric material formed by the XDapparatus, which has adhesive between a layer of aligned warp yarns onone side and a layer of weft yarns substantially perpendicular to thewarp yarns on the other side, is fed to the pressure laminator, eitherdirectly (as with the flat bed laminator described above), or by a feedroll. The composite material is drawn into the pressure box by the drivebelts, through the inlet seal and into the pressurized heating zone. Theheating zone melts the adhesive between the fabric layers and causes theadhesive bridges to flow and spread between the layers of fabric. Thepressure holds the fabric in place, preventing shrinkage, and thecooling zone, which has the same pressure as the heating zone, cools themelted adhesive and fixes the bond between the layers of fabric. Thisnonwoven fabric material has very high strength characteristics andantifray characteristics, and represents yet another especiallypreferred embodiment of the present invention.

SUMMARY

It will be appreciated that one or all of the above-described nonwovenembodiments could be run through one of the adhesive applicationstations a second time so that adhesive would be applied to the laminateand then the adhesive covered laminate secured to the warp yarns orother substrate to form a new warp yarn material that has the laminatesecured thereto for passage through the nonwoven apparatus again so thata multiple layer laminate of warp and weft yarns could be laid down. Itis also within the realm of this invention to include multiple weftapplication stations spinning in the same direction or in oppositedirections to create various weft yarn angles of lay down. Yet anotherpotential embodiment is to laminate films on the front or back of thenonwoven product of the invention for structural or performance reasons.Alternatively, a film could also be positioned between the warp and theweft yarns so that the yarns would then provide structural support tothe film.

A key feature of the nonwoven apparatus of the present invention is thatit provides a method of engineering a nonwoven article. The weft yarnscan have different properties, the warp yarns can have differentproperties, the distance between warp yarns and the distance betweenweft yarns can be adjusted, the amount and type of adhesive can beadjusted, the angle of the weft yarns relative to the warp yarns can beadjusted and the multiple weft application and warp supply stations canbe used to create a multitude of different structures very efficientlyand at high speed. As a result of the above, the nonwoven product canalso have the same or different strengths in its warp and weftdirections.

Although the present invention has been described with a certain degreeof particularity, it is understood that the present disclosure has beenmade by way of example, and changes in detail or structure may be madewithout departing from the spirit of the invention as defined in theappended claims.

1-157. (canceled)
 158. A method of forming a non-woven fabric,comprising the steps of: providing a supply of elongated side-by-sidewarp yarns forming an elongated warp sheet, said warp sheet includingadhesive bridges on only one side of the warp sheet, wherein theadhesive bridges extend between adjacent warp yarns on said one side ofthe warp sheet to hold the warp yarns in a substantially parallel andnon-twisting relationship; forming the warp sheet into a substantiallycylindrical configuration, wherein the adhesive bridges on said one sideof the warp sheet are exposed; moving the cylindrically-formed warpsheet along a linear path while transversely wrapping weft yarns aroundthe cylindrically-formed warp sheet; adhering the weft yarns to theadhesive bridges on said one side of the cylindrically-formed warp sheetto form a substantially cylindrical non-woven fabric of said warp andweft yarns; and cutting the substantially cylindrical non-woven fabricalong the linear path to free the non-woven fabric from its cylindricalform.
 159. The method of claim 158 wherein said one side of the warpsheet includes an adhesive scrim adhered thereto to form the adhesivebridges.
 160. The method of claim 158 further including the step ofapplying heat to soften the adhesive bridges after wrapping the weftyarns around the cylindrically-formed warp sheet.
 161. The method ofclaim 160 further including the step of cooling the adhesive bridgesafter softening the adhesive bridges with heat.
 162. The method of claim158 further including the step of unfolding the non-woven fabric, afterthe step of cutting the substantially cylindrical non-woven fabric, toform a relatively flat non-woven fabric.
 163. The method of claim 162further including the step of accumulating the relatively flat non-wovenfabric on a drum.
 164. The method of claim 158 wherein the weft yarnsare pulled from a plurality of circumferentially spaced spoolssurrounding the linear path of the cylindrically-formed warp sheet andare transversely wrapped around the cylindrically-formed warp sheet.165. The method of claim 164 wherein said plurality of spools aremounted on a drum that is rotatable about the linear path.
 166. Themethod of claim 165 further including the step of delivering all of theweft yarns from the plurality of spools to one end of the drum along thelinear path before transversely wrapping the weft yarns around thecylindrically-formed warp sheet.
 167. The method of claim 166 furtherincluding the step of providing a uniform level wrapping of the weftyarns around the cylindrically-formed warp sheet at said one end. 168.The method of claim 158 further including the step of maintaining apredetermined tension in the weft yarns before wrapping the weft yarnsaround the cylindrically-formed warp sheet.
 169. A non-woven fabric madeby the method of claim 158, said non-woven fabric comprising: a firstlayer of substantially parallel warp yarns; a second layer ofsubstantially parallel weft yarns, wherein said warp and weft yarns aresubstantially perpendicular to each other; and adhesive bridgespositioned only between inner facing surfaces of the first and secondlayers to adhere the first and second layers together, wherein theadhesive bridges do not extend to outer surfaces of the first and secondlayers.
 170. A non-woven fabric as recited in claim 169, wherein theadhesive bridges are positioned in a random and discontinuous mannerbetween the first and second layers.
 171. An apparatus for forming anon-woven fabric comprising: a supply roll of elongated side-by-sidewarp yarns forming an elongated warp sheet, said warp yarns held in asubstantially parallel and non-twisting relationship by adhesive bridgesthat extend between parallel yarns, wherein the adhesive bridges areapplied to only one side of the warp sheet and do not extend to anopposite side of the warp sheet; a closed loop flexible transfer beltfor moving the warp sheet along a linear path; motor means driving thetransfer belt along its closed loop; a folding system for folding thetransfer belt and the warp sheet into a substantially cylindricalconfiguration extending along the linear path with the adhesive on saidone side of said warp sheet being exposed; an elongated mandrel,extending along the linear path, for supporting the transfer belt andthe warp sheet in said substantially cylindrical configuration; a weftyarn applicator for transversely wrapping weft yarns around thesubstantially cylindrical warp sheet as the warp sheet moves along thelinear path through said applicator; means for adhering the weft yarnsto the adhesive on said one side of the substantially cylindrical warpsheet to form a substantially cylindrical non-woven fabric of said warpand weft yarns; a cutter for cutting said substantially cylindricalnon-woven fabric along the linear path to free the non-woven fabric fromits cylindrical form; and a take-up roll for accumulating said non-wovenfabric once it has been freed from its cylindrical form.
 172. Theapparatus of claim 171 wherein said one side of the warp sheet includesan adhesive scrim adhered thereto to form the adhesive bridges.
 173. Theapparatus of claim 171 further including a heater for softening theadhesive after wrapping the weft yarns around the substantiallycylindrical warp sheet.
 174. The apparatus of claim 173 wherein theheater is contained within the elongated mandrel.
 175. The apparatus ofclaim 173 further including a cooling system for cooling the adhesiveafter softening the adhesive with said heater.
 176. The apparatus ofclaim 175 wherein the cooling system is contained within the elongatedmandrel.
 177. The apparatus of claim 171 wherein the folding systemincludes a pair of elongated rods disposed at an angle relative to thetransfer belt and positioned for engaging the transfer belt andprogressively folding the transfer belt into the substantiallycylindrical configuration as the transfer belt moves linearly along saidrods.
 178. The apparatus of claim 171 further including an unfoldingsystem for unfolding the non-woven fabric after cutting thesubstantially cylindrical non-woven fabric to form a relatively flatnon-woven fabric prior to accumulating the non-woven fabric on thetake-up roll.
 179. The apparatus of claim 178 wherein the unfoldingsystem includes a pair of elongated rods disposed at an angle relativeto the transfer belt and positioned for engaging the transfer belt andprogressively unfolding the transfer belt into a generally flatorientation as the transfer belt moves linearly along said rods. 180.The apparatus of claim 171 wherein the weft yarn applicator includes aplurality of circumferentially spaced weft yarn spools surrounding thelinear path of the warp sheet.
 181. The apparatus of claim 180 whereinthe plurality of spools are mounted on a drum that is rotatable aboutthe linear path.
 182. The apparatus of claim 181 wherein all of the weftyarns are delivered from the spools to one end of the drum along thelinear path before being transversely wrapped around the substantiallycylindrical warp sheet.
 183. The apparatus of claim 182 wherein the weftyarn applicator further includes means for providing a uniform levelwrapping of the weft yarns around the substantially cylindrical warpsheet at said one end.
 184. The apparatus of claim 181 wherein the weftyarn applicator further includes a yarn tensioning device formaintaining a predetermined tension in each of the weft yarns beforetransversely wrapping the weft yarns around the substantiallycylindrical warp sheet.
 185. The apparatus of claim 171 wherein the weftyarn applicator further includes a yarn tensioning device formaintaining a predetermined tension in each of the weft yarns beforetransversely wrapping the weft yarns around the substantiallycylindrical warp sheet.
 186. The apparatus of claim 185 wherein the yarntensioning device includes an adjustable spring to provide apredetermined frictional engagement with each of the weft yarns passingthrough the yarn tensioning device.
 187. The apparatus of claim 186wherein the yarn tensioning device includes a fixed plate and a movableplate that is spring biased towards the fixed plate, and wherein thespring causes frictional drag in the sliding movement of a weft yarnbetween said plates.
 188. The apparatus of claim 185 wherein a separateyarn tensioning device is provided for each weft yarn.